We too have full overlay cabinets.
When the countertop company we used templated, they took into account the extra depth of the doors and extended the counters accordingly.
As far as shimming goes, the only shimming done was to level the countertops.
Since our kitchen reno started with a "to the studs demo", there was very little shimming to do as the new floor was already level.
I'm attaching a link to our completed kitchen so you can see the countertop depth and the full overlay cabs.

Here is a link that might be useful: Black & White Kitchen

"Anyone out there shimming their counters for overlay doors?"

Make the top rail of the face frame taller.

There is no need to shim up on account of a full overlay door. The only shimming done should be to level the material. Even with full overlay on frameless there is still enough of a reveal for the drawers to open properly.

The standard counter these days is more like 25 1/2" or so. But you have the flexibility to make it whatever you want, so long as you are not buying post formed laminate.

Standard cultured marble tops for vanities are 22" on a 21" cabinet, which I have heard several folks complaining about. You may want to ask you sales person about ordering a custom top for you bath, made a little deeper instead of settling for the standard mold.

You only need to do that if you have counters with an edge buildup that would hang over the door if not underlaid with the correct depth of plywood. If you get 3 cm stone, it rests directly on the cabinet carcass with no issues. If you get 2 cm stone and have the edge built up to 4 cm, then you need to have the plywood underlayment also match the 2 cm depth in order for the stone to not interfere with the cabinet drawers or top rail.

I just had my counter tops measured last week. I have full overlay doors and drawers so the fabricator said they would do a 1 1/2 inch overhang in relation to the cabinet depth to allow for the doors and drawers. My counter tops will be 26'' deep. They do not raise them up with plywood but the fabricator did say that some edge styles would not work with the full overlay doors and drawers. He brought sample pieces of granite with the different edge styles so I could see how they would look with my cabinets.
You may want to get some edge samples and try them out on your cabinets.

Thanks for all the info and experiences! The KD at Lowes said nothing about the overlay doors. He was just going to do a 25 inch counter. He actually made quite a few mistakes along the way which fortunately I caught beforehand. I found that you have to be very careful and look out for things yourself. Although I was on top of that one, I somehow missed it during the vanity top order (custom) and just followed along. I'd thought I was being very careful. I'd even been to 3 different places. One was even a specialty showroom. No one accounted for the doors. It can be pulled out slightly but the back wall caves in a bit in the center so it's limited. It still looks a bit short and could use more drip space. I hope it's not too bad. Time will tell. My mother's is smack up with the cabinets which I'd never noticed.

I'm getting laminate and wanted my contractor to install it. It's twice as much for the store to do a template and install. I can't see paying that much for a laminate and don't trust them with the install. But I also think (know) my contractor is inexperienced with all this in terms of ordering. They seem to be guessing.

With the shimming, I see I misunderstood. I just happened to notice the tops of the doors and drawers looked visually cut off with a 26" overhang and wondered if it looked odd. Now I wonder about how the actual top is going to fit on. That 1 1/2 inch thickness is just a front edge piece that slips over. The counters are only 3/4 inch plywood. There's only 3/8 from the top of the cabinet to the drawer fronts. Certainly these companies have worked all this out correctly! The estimate must be for the shimmed version but it wasn't mentioned. I had ordered the cabinets there. My contractor didn't mentioned it for ordering. Linked is the website where it talks about ordering with shims. I have no idea who this company is.

The whole thing with those in the business not addressing the overhang issue really irks me. Most people do not even think about these things. It also doesn't look quite right when they're short, imo, although I seem to be seeing it done that way all the time. Cabinetry can get really damaged with the drips. These are very costly mistakes.

Here is a link that might be useful: Measuring counter tops

Overhang in an of itself is not going to protect from spills.

You'd need a kerf cut on the underside of the top and it' have to be past the front edge and handle/knob for it to be of use anyway. With that much overhang you'd easily strain you back reaching for something near the back of the top, not to mention limiting your reach for any level of your wall cabinets!

In addition if you have any drawers , you now have a guaranteed knuckle buster with that much overhang.

If you want to contain spills you need to have a "lip" on the front edge that rises above the flat plane of the main body of the countertop. This is more practical and ergonomic - but presents it's own problems.

Don't take this the wrong way but, It's simply easier to be less messy and gain hand eye co-ordination. Not as fun or expedient though.

It does allow some room for it to drip down onto the floor instead of onto the face of the cabinet. Yeah, best to be neat!

I was checking out laminate tops yesterday and they all seem to have a flat edge all around resting directly on the face. So I don't understand the shim thing on that website.

On the end of a run, how much overhang is done? How about where the range slides in? My contractor said to go flush at the range and 5/8" on the open sides. He was also going to cut the one end at the wall. Is this typical or should we provide exact measurements at the front and back to have any wall irregularity there might be built that way? Has anyone provided their own template information? The KD was vague, wanting to sell the install.

I'd wanted to do a thinner top without the edge buildup. That would be about 3/4 inch I believe. Now I see the eased type of edging (top and bottom) can only be done on the fronts. There's an area that has two open sides. I'm not sure how that's going to look having the front eased and the sides standard square. What do you think?

Would a 3/4 inch counter done in the standard square look okay? I do like the way 3/4 inch doesn't scream laminate but am wondering with the edging problem. I'm thinking I'd try painting the brown edge like someone here did with a soapstone laminate (they used a black sharpie pen).

Thank you for your help in figuring this out!