will I be able to plane it effectively?

What are you asking -- what is "effectively"?

How would strangers know what you are capable of?

Effectively, meaning will it flatten,square,true imperfections?

Make sure the Capital key gets repaired. lol

If you have the butcher block oriented with end grain on the surface it won't plane well. You'll need to put it through a drum sander.

will I be able to plane it effectively?

If you want helpful suggestions/answers, you need to provide more information.

How would strangers know what you are capable of?

Show a picture of your countertop. Say how you plan on planing them.

If you wanted the tops to finish out at 1-1/2", then your squares should have been rectangles.

Ok,when I said plane,I should have stated I would plane it one of two ways (1) a benchtop planer (2) a router with a spoilboard bit on a sled.these countertops are being built from pecan that I sawed up at a friend's sawmill,the pecan has been cut on my table saw 1-1/2 square.A joiner would do me absolutely no good as the wood bows ( air dried for a couple years).titebond is stronger than the base wood so when I clamp the wood together it will be fine.my issue is with the high/lows on the surface,one slat may be taller than the next one by no more than a 32nd.

What are you wanting to know? You plane the wood to eliminate the highs/lows.

That's not butcher block, it's simply a wide slab produced by gluing up multiple boards. Joint them flat and plane them to the same thickness prior to glue up. If the cupping of individual boards is excessive, rip them into narrower widths so they can be properly jointed and planed. You can use biscuits or floating tenons to keep the surfaces aligned during glue up.

Give me a 4" wide belt sander and a 40 grit belt and I'll have that perfectly flat in 20 minutes.

Butcher block is available in edge grain or end grain configurations. The OP can utilize the material they have to create an edge grain countertop.

There is no difference between face grain and edge grain for counters… Butcherblock was originally made with end grain because it cuts into the fibers rather than across them.

Try this to understand. Take a tooth brush and a sharp kitchen knife, turn the toothbrush face up and slice into the bristles. Your knife will separate the bristles but will not cut them. Now turn your toothbrush sideways and cut across the bristles. You will now remove bristles. The same would happen from the top of the toothbrush.

Realistically, we don’t chop on counters anymore and the difference is moot. So, we started making faux butcherblock with edge grain (btw… in flat sawn lumber the face grain of the top and bottom cuts of a log is going to be the same as the edge grain of the middle cuts).

So I would argue that this counter isn’t technically butcherblock, but then again, neither are 90% of the butcherblock counters sold today.

I don’t really understand the specific question. Counters and slabs are almost always flattened with a router sled (unless you have a giant CNC router).

If you are close to your final dimension on the counter, then you should glue some scrap to the sides so you don’t get tear out.

If you are using wood for the guide rails on the planer sled, run them through the jointer first. If you don’t have a good jointer then attach a couple of pieces of steel to the top to get a flat edge (you can use plywood if you are less than 8’ in length). The Wood Whisperer has a great video for first time router sled users. https://m.youtube.com/watch?v=qtkBZHLJyD0

My confusion comes from the fact that if you are aware of router sleds and spoilboard bits then I suspect you are more informed than most here. I am happy to offer more specific advice, if you can give me a more specific question.