The Grip ... Gun Being FLAT
Full size 5" and 4" , only difference is the bbl length- grip is the same, and they are FLAT.
IF the 4" is a LT WT version ( alloy and steel) Concealment is the same - The savings in weight is what makes it comfortable to some folks.
Most folks, even ladies carry a full size ( 5") all steel 1911 with NO problem.
Folks do have other factors that play in - Anatomy , and I'm not just speaking of the differences b/t men and women. Other factors such as back, hip, or any other problems or surgeries.
The KEY is a good belt and holster to fit the individual proper. Makes no never mind really id 5" or 4"....other than the weight ...you gotta stick a mag in the gun somewhere and they are the same size on both length guns. They all have the ame width.
Me - personally - I am not real keen on 1911 styles less that 4 1/4 " . This is related to reliablity of 1911 platform. I also have another "quirk". All my mags fit the full size 1911, I don't want to have to buy new mags that won't fit a full size gun. Toss in the dealie about Mr Murphy sticking the wrong mag in the gun, or rd count being different than I train with, or the mags themselves being onery or...
I also subscribe to the theory of having multples of same gun. Redundencey allows the use of same mags, same holters, same belts, and everything works the same. Even a Commander Size wil work in a full size IWB holster
Honest - I can do a 5" just as easy as any of the variations of the 1911. 1911's are known to conceal better than many , if not most other platforms.