I have owned 5 Sigs over the years and currently 4 live at this address: In ascending order of caliber; P238, P239, P226 & 1911 SS Carry. I had a P245 a while back but didn't care for a compact .45.
The 1911 came with 2 magazines while the others came with 1 mag. I figure either of your 1911 choices will come with 2 mags. However, I feed my other 1911 (STI) only Wilson Combat mags and it loves them. Since I just acquired the Sig 1911 SS Carry, I don't have a report on that compatibility yet....but I will soon
So, good luck with your difficult choice, but either will make you smile. And always remember, once you get a 1911 more will follow you home. They are addictive.