I would definitely reposition the thumb cluster on the KA to be slightly lower (no more than 1cm lower really), however I didn't find this to be a problem for me.
I rest my hands with the pinky/thumb at about 15' (that is, the hand is is not with the palm flat but at about 45" compared to the keyboard). If I extend pinky and thumb, they're naturally on the same plane.
If I could tent the halves though that 1cm of difference would be nice.
On the kinesis I can hit comfortably ctrl+alt + "=" (and pretty much any other key on either half) with thumb+pinky, on both halves. Holding shift is also entirely possible with pinky or ring, even in combination with ctrl/alt/ctrl+alt and while typing with the remaining 3 fingers.
Seems a stupid thing to do when written, and maybe it is, but hey .. emacs, and I'm doing it with ease actually. I normally chord the modifiers with one hand and type with the other, but if there's a weird combination I'll just do it with a single hand too.
I could definitely 3d-print an entire glove80 mock if I found a model.
For a long time I've been pondering about just 3d-printing a modified dacytl to fit my own preferences, but it's one of those things I wish to just pay for, have some QC without wasting time, and be done.