Can you put your pots and pans in the drawers below the cooktop? Seems like you are trying to fit a lot of stuff into this space... just because the pot/pans and dishes will take up so much room. What other cabinets will you have? Probably posting even a rudimentary layout would help, though.

Measure the stuff you want to put in there, and divide it accordingly, to the nearest reasonable increment.

Yes, measure! Then don't forget that interior drawer space will be about 3 inches less than outside measurement of the cabinet (2x side wall thickness + 2x drawer side thickness + a little for clearance and maybe glides). Maybe a tad bigger, but 3 in is easier to ballpark.

I would not advise 12 inch drawers unless they are just the top of a pullout. My frameless 12 inch drawer is just big enough for pot holders and trivets. Thankfully, I only have one that size.

A 4 drawer 18-21 inch or so (whatever will fit your placemats) might be useful. That would be a good size for flatware (maybe even a double layer flatware drawer? I love those!), placemats, serving utensils, and the larger bottom drawer might fit your napkins or tablecloths.

The pots and pans should mostly fit under the cooktop. That would leave 27-30 in for your cooking utensils (top drawer) and dishes below that.

I have 2 x 27 in frameless drawers that hold all our everyday pots/pans. The top drawer there holds a knife block and cooking utensils. Roasting pan, wok, cast iron grill pan, and a few larger/rarely used pieces are located in drawers under the oven on the other side of the room. I also have 2 x 30 in frameless drawers for dishes. That's plenty, I actuall wish I had shorter drawers as there is a good amount of wasted vertical space. Plus I have enough room for towels in the bottom drawer with the dishes. I have drinking vessels still in the uppers.

All our regular pots & pans fit in the two 36" deep drawers below our cooktop.

My gluten-free pots & pans fit in two 24" deep drawers (I have fewer pots & pans for GF cooking). I also have a KA Mixer Bowl & attachments, a toaster, and a waffle iron in those two 24-inch drawers (all GF, of course!)

Our glass casserole dishes, etc. are in a couple of 30" drawers - spread out b/c of their weight. Those drawers have quite a bit of "white space" (i.e., empty space).

Unless you have a very large collection of pots & pans, I think you should be able to fit them all under your cooktop. So, that leaves those 48 inches of space for other storage.

I think two 24" cabinets would work well. The top drawer of one could hold silverware; the other could hold cooking utensils.

One could be a 4-drawer stack, with two shallow & two deep drawers - the second shallow drawer could hold placemats (and possibly other, similar items).

We have one 24" cabinet that's a 4-drawer stack with 3 shallow drawers and 1 deep drawer. It houses:
(1) Silverware
(2) Wax paper, plastic bags & wraps (foil & parchment are in the baking center - near the ovens where they're used)
(3) Extension cords and the like
(4) Bread (gluten-containing bread, not GF)

Thanks, everyone. I agree that the majority of the pots and pans should fit under the cooktop. I'm hoping to slip in a utensil drawere there as well-- some people seem to manage that with the Bosch.

I also thought that 12 inch drawers would be too narrow to be useful. I guess I will try a couple of plans, one with 24 and 24, one with a large and small side, not sure what that should be yet. Thanks for the reminder about correcting for cab and drawer thicknesses, too-- I'm never quite sure how much to add in for that!