I like going the route of 30" vanities with 19" left for a drawer stack or hamper. In this case, you would buy the vanities without tops and either have a single countertop w/ integrated sinks made for the space (HD has a service for this) or purchase drop in or undermount sinks and use laminate, granite, or quartz for the countertop. Don';t forget you can do spacers on either side of the vanities if you need to make up for any difference in available component sizes. In fact you may want to do spacers on the ends if the vanity is right at a doorway. There are a few different options for setup-- 1) As the vanities are standalone, you can order ones where both sides are finished or 1 with left side finished and 1 with right side finished. Then you can use just a regular hamper in the empty space underneath the counter that slides into place. 2) Order vanities and a drawer stack to place all in a row under the countertop. Finished sides will not matter in this scenario 3) Order vanities and built-in hamper unit to place all in a row under the countertop. Again, finished sides not an issue. Just remembered, Lowe's has a semi-custom vanity program you should probably check into. If I remember right, it was reasonably priced. I can't remember the name of the program though. Your local Lowe's should be able to help out though. That may be the easiest way to go. Hope this helps!

We are right now doing what you are considering. (Well, our contractor is doing...) We've owned this house for a very long time, and never set foot in the 4th tiny bedroom (really just an office, no closet). But thought we would hurt our property value if we used that office as our closet (our home is our largest asset, so it matters to us if we renovate in a way that lowers value). We live in such a high COL area, we can't move. So we finally decided to (1) add the master closet to the master bath; and (2) put a door from the master bedroom into the office, to make it the new master closet. Turns out in my area it helps value to have a larger master bath and closet - even at the expense of losing the small 4th bedroom/office (tons of homes in my area have this layout). I checked with real estate agents and watched sales for a couple of years to make myself comfortable with this decision. As to layout: similar to your drawing, ours will be 6'x12' with the closet added on). We have a 3.5'x6' shower at one end like your drawing. Left the toilet (saves about $4k in my area, party b/c old house plumbing issues). Then, do a short wall about 30" wide x 42" tall at the shower: (1) have the shower door pivot (both in and out) there, so you can reach the shower valve on the inside of that half wall - no getting wet!); and (2) put the 2nd vanity (30" for us) against your window wall and that 1/2 wall. Your door is at the other 6' end; ours is on the 12' long wall, so a bit different but hopefully this makes sense?! I.e., I think you can fit in two 30" vanities (we have a 30" and 36"), big shower, keep toilet there, and have a huge master closet from your (unused??) bedroom. I personally like the 2 separate vanities vs. a long 60" - and it saved so much for us b/c it kept the toilet in its place - but YMMV. Sorry to ramble! Hope that helps. I'm so thrilled this is happening now to my home, and only wish we had done it a decade ago!PS I, and the real estate market I'm in, prefer a large master bath to large closets if there is a 4th bedroom (as it will get converted to a closet anyway). Of course that varies by market, person, etc... but thought I'd say that as I struggled with this decision for many years.

I think smaller or same size, definitely wouldn’t go wider than the cabinet.

If you'll have a separate linen cabinet, do you need a lot of vanity storage? Is this a secondary bathroom? I think the spacing around the toilet really depends on who you expect will be using it. If it's a kids bathroom, 15" is probably okay, but if it's going to be regularly used by grownups (especially men or larger women), you are going to want more space around the toilet. Our master bath has a toilet closet that's only 30" wide and my husband pretty much refuses to use it. I had to remove the tissue holder from the wall just so he didn't run into it. We're about to remodel and I'm allowing at least a full 36" for the toilet (and it' won't be in a coffin - I mean closet.