I own and carry both a .40 and .45, it depends on what I am doing and what I am wearing, OC or CC and many other factors.
Don't worry about the lawyers, if you are going to defend a life, "overkill" should be your last concern. .05 more projectile diameter is not going to sway a DA or jury, if it went to trial, in my opinion.
If it's for OC only, the size difference of the guns matters little, number of rounds and weight might be a concern. There are so many variable when it comes to deciding something like .40 vs. .45 that I suggest you just go with whichever one you are most attracted to. You probably already know which one you want more, so go for it.