I think your on the right track, with your leaning towards the Sig, you really cant go wrong with that.
But also think of what you wear everyday, Do you want that weight, and will you decide not to carry because of the lack of comfort and lack of ease in carrying a large cal pistol.
I carry a Smith & Wesson Airweight 442 (black) .38 Special with +P ammo of course. It is super light and with an inside the pant holster I can carry it even while wearing training pants.
I was not a revolver guy either but the weight plus the preformance you get from a +P .38 is not bad. Price was also a factor.
Also think of yourselve under the pressure of a firefight, try to pick a weapon that is easy to use. A revolver is simple, pull out and shoot, no safety or thinking did i chamber a round. Yes these may seem like stupid words but a novice sometimes makes those mistakes.
Bottom line pick a weapon you feel most comfortable with, I dont care if you have a .50 cal, if you make a simple mistake or didnt carry because it was uncomfortable to you, then you made the wrong choice.
But some snap caps (orange practice ammo) so that you can load and function check your weapon while at home. Practice often and know your weapon.
The secret is not to have the fanciest gun or biggest, but to know how to use it when the time comes.