During the winter, I wear a coat with a larger gun under it.
I carry a Glock 30, all year around without any concealable problems. With the right IWB holster, you can comfortably hide a full sized 45 while wearing cargo shorts, tank top and flip flops. All you gotta do is carry it at the 4:30 position (between your rear right pocket and right side pocket.
No need for single stack guns, downsized guns or guns with grip lengths so short you need extended mags or grip extensions to shoot comfortably.
I prefer the Glock over the 1911 because it holds more rounds, weighs less and is a much faster shooting platform.
I'm a little cautious about "bumps" under clothing. The U.S. now has too many people who are afraid of firearms. They have a phobia caused by our educational system and media propaganda. Police officers can be the same way. Things can get ugly really quickly.