You are correct, you will an extra 1.25"
Maybe you could give some to the toe?

That's a good idea. An extra inch down there would probably mean more than an inch somewhere else.

Go with the 4-drawer stacks for sure. You can use the shallower drawers for your frying pans. The convenience of grabbing a pan, without having to unstack a pile of stuff from on top of it, is great.

You don't have enough stuff to fill four deep drawers anyay. Neither do we, so we went the same way in our range run.

I put some pics in the attached thread about a week ago --see second post in the thread.

Here is a link that might be useful: Drawer stack configuration

I used 4-drawer stacks for most of my utensils and the like. I also thought that trying to fish for the, in a jumbled mess of deep drawers would drive me to drink. Some of my stacks are also pictured on the thread Taggie linked.

Thanks Taggie and BG. You've made up my mind.

"...Our countertops are 2cm with no built-up edge..."

Is this a stone countertop? If so, there should be a plywood subtop that will sit b/w the cabinets and the counter.

3cm stones do not need the subtop.

I hit submit too soon...

Personally, I would not take a chance and not put a subtop under the counters, I don't care how "small" the pieces are. But, it's up to you...

I have one 4-drawer stack in my kitchen that holds:
Silverware
Wax paper, plastic wrap, plastic bags (snack, sandwich, quart, gallon, and 2-gallon sizes)
Extension cords, power cords, other electrical-related items
Bread

The shallower drawers are perfect for the contents in the top three drawers while the deeper 4th drawer is perfect for bread.

I designed my current kitchen with with 3-drawer stacks; 6,12,12 and I will be doing more 4-drawer stacks in the next kitchen. I love love love my drawers but for me I end up stacking stuff in some of the deeper drawers so having more shallow drawers will be quite luxurious. I also have frameless cabs. All that to say that you are on the right track :)

You said your base cabinets are extra deep at 30". Make sure the cabinet guy knows to make the drawers inside the cabinet extra deep as well. Some of them still put the same size drawer in a deeper cabinet which wastes all that space at the back of the lovely deep cabinets !! What is the width of your two drawer stacks ?

My kitchen does not follow the drawer heights rule where all the stacks line up visually around the kitchen (6 12 12 or 6 6 6 12). Although, something that helps is that my stacks are caddy-cornered across the kitchen with appliances and base cabinets with doors separating them ... it would be very hard to look in any direction where you could see the "mis-matches" at one time.

I have 2 stacks that are 6 12 12 and 2 stacks that are 6 6 9 9. The 12's are good for storing pans and bakeware vertically (see link below that has LOTS of pics in post on Mon, Sep 24, 12 at 10:18). I also love the bottom two 9's in the other stacks which are useful where a 6 would have been too shallow and a 12 would have been too deep.

Another way you can gain an inch or more in your main drawers is to decrease the height of your toe kick to 3.5". Aliris19 did that in her kitchen. But, that would make your toekick drawers more shallow, so it depends on what you plan to put in yours. I have also seen where some people have made the toe kick part of the bottom drawer. It follows the contours so the front 4" of the bottom drawer is more shallow and the rest of the drawer is deeper into the toe kick space. I hope that explanation makes sense ?

Here is a link that might be useful: http://ths.gardenweb.com/forums/load/kitchbath/msg091306457777.html