What is the size of the bathroom? Where will the sink be placed? What is FAIRLY LARGE??

Until you show the space your question is a mystery meat.

( The chat image is not great , sorry. rather a "clutter"

Is it a powder room ? A wet bath? What and where is the plumbing? How tall is the ceiling?

- Curious why you are limiting yourself to a 30" sink if the bathroom is large.

- No, these lengths don't look good together. Glass shelf and mirror should be narrower than sink.

- The style of medicine cabinet doesn't match the style of sink.

Scroll these pics for lots of images of pedestal sinks with glass shelves and recessed medicine cabinets.

https://schaferco.com/portfolio/rooms-and-details/bedrooms-and-baths

Here is OPs AI rendering ...

So you are placing the bottom of the medicine cabinet 26" above the sink?

You must be 6'6" tall to even think that this is "normal" ergonomics! LOL

Why the shelf? You will end up with visible clutter. Why not just get a taller medicine cabinet?

The whole thing is off, scale wise.

If you have tall ceilings, you should take advantage of that and visually balance the space with proportional elements.

These Robern medicine cabinets are 48" tall and the bathroom ceiling is 10 ft. high.

Lots of storage for everyday items in the 24" x 48" medicine cabinets and no need for shelves that get dusty.

Both very short and very tall people can use the mirror!

I would judge this as one full wall composition rather than as separate sink, shelf and cabinet pieces.

With a 30-inch pedestal sink and a 42-inch floating shelf, a 36-inch recessed medicine cabinet does not sound automatically too small. In many bathrooms, that can actually feel calmer than pushing the cabinet too wide and making the wall top-heavy. The more important question is whether the cabinet width, shelf width and the spacing for the sconces feel intentionally related when you stand back from the wall.

From a production and QC perspective, I would be careful not to size the cabinet in isolation. Recessed cabinets, especially in white new-construction bathrooms with taller ceilings, can start looking underscaled or oversized depending on the light placement and the visual weight of the shelf below. If you want side sconces, I would tape out the cabinet and fixture positions on the wall before ordering. That usually answers the proportion question much faster than dimensions on paper do.

My instinct would be to keep the cabinet comfortably proportioned to the sink zone, then let the sconces and finishing touches complete the scheme rather than trying to make the cabinet carry all the visual presence by itself.

Pedestal sinks are an awful idea in any bathroom that gets any use. Where do you put things? Are kids going to be using it so they can get water everywhere? Not sure what the style or price point of the house is, but the above image is not at all appealing.

we have a pedestal sink in a kids bath (older home with tiny baths so didn't have choice) - we have a large medicine cabinet and then another large cabinet for more closed storage) - I would not put one in a large bath as vanities provide so much better storage and countertop utility. Regardless, if it were me I'd skip the glass shelf - gets gross pretty easily and also pushes the mirror up really high

I would also get a single centered faucet to give you more space for setting down things like toothpaste, water glass etc. We have one from a Studio McGee/Kohler collab that is hefty and feels nice - we also have the Kohler Purist in a PR

I love Memoirs sink. In this house I have 4. In my last house I had 6 and the house before that there were 4. I did the 30", also. In a larger bathroom you will have the option of lovely storage pieces.

IMO pedestal sinks are a must when space is tight but I would never do one in a large bathroom where a nice sized vanity provides so much storage . I do vanities with all drawers even under the sink and then maybe a tall cabinets for towels .