I was just able to get my arched Dawson msh into my STI plastic grip and absolutely find it easier to acquire my sights. I had a flat msh on a 1911 that I sold, and found the flat just didn't work with what my hands wanted to do, and I was too stubborn to practice with it till it worked.
As much as I like the arched I may eventually get a wedge to see if it feels any better, but right now I at least know I prefer arch to flat.
It's always gonna come down to preference as usual. What works for one may not for others.