For concealability, the 1911 is probably going to be easier. However, I'm 5'7" and carry a S&W Model 60 with a 3" barrel, which is a close cousin to your SP101. After I figured out how, I found that I can conceal it on-body without much trouble except in the middle of summer when I'm wearing only a t-shirt and shorts. (Then, I just open carry.)
So you might want to try both, and if you find that you can conceal the SP101 easily, you have options about which to carry. Having choices is IMHO a good thing. ;-)