I know I am a month late to this party but I've attached a screenshot of my layout here.
I am actually on a new KeyMouse 3 now (was using the earlier version for a couple years prior) and haven't quite updated everything to a new layout, but the gist of it is here. I have mouse toggle on the middle button of the left hand since I generally don't want that motion for gaming. Honestly, I have tried gaming with both devices in the past and almost always prefer KeyMouse on the left and my right hand with a standard MMO Gaming mouse. That said, the KeyMouse 3's increased pointer accuracy could have me rethinking that, especially for strategy games.
In addition to moving the WASD over as you say, I also have CTRL and Shift on thumb buttons because I use them so much and find that to be a really comfortable and convenient press. Beyond that, I just have the most common buttons found in games somewhere on the device for easy access.
Happy gaming!