The Dynons that you refer are quite old in a rapidly changing world of avionics. I think you'll find most more modern units are much brighter.
I have used the GRT mini and Horizon units under a bubble canopy with no problems. The G1000 would most likely be fine at a vastly higher budget level, but G3 and G5 and most of the newer units should be fine.
Dig into the literature and you'll find most are in the range 800-1200 Nits, whereas the older ones are about 400.