Go with the wide for 2 reasons.
1) yes you will have toe drag on deep carves. I have toe drag occasionally on deep carves with a 9.5 on a mid-wide (25.5cm)
2) a L/XL base plate will hang off a reg width board. You'll get some drag from that alone in deeper snow.
A wide board doesn't ride much different than a reg width board, it give you more surface area, which has multiple benefits in itself (which is why I prefer mid-wide's).
Some people are going to bitch about how wides are slower edge-to-edge, but the leverage of how high your footbed sits above your base, and the boards side-cut and camber profile, will determine your edge-to-edge transfer far more than the .5-1cm difference of board width ever will.
There's no reason to ride a reg width board with an 11.5 boot.