I've found no consistent effect of bore height.
The problem in sorting this out is that you'd need two otherwise identical pistols with different bore heights. Comparing different pistols with different bore heights is meaningless due to multitude of other factors that you can't correct for.
I don't care about perceived muzzle flip - the distance traveled by muzzle is widely considered irrelevant. I do care about my timer's data. According to my timer, I get best splits on high-probability targets with my lowest-bore pistol, but I get best splits on low-probability targets with a pistol that has a highest bore axis. Go figure.