I take a completely different tack. I do not think that any gun fits my hands, etc. So, I never consider that aspect of buying a gun. What I believe is, if you practice enough with the gun in question, you will eventually adapt to it. The military has been demonstrating the truth of that statement for years. There was only one handgun...the 1911 .45, and only one rifle, the M1 Garand.
If you cannot adapt to those guns (as an example), you have not practiced enough with them.