When you really like a gun's reliability and pedigree, and it was designed as a single stack, the emphasis is on the gun: Sig P6, Russian Makarov (.380), Spanish Star BM.
For a while my only carry was the .380 Makarov, and switched to the P228 and CZ PCR as carry, because they are 9mm and are easy to conceal, very adjustable in the Remora IWB.
The only reason the 9mm Star isn't carried is because of its "cocked/locked" design and I'm a Lefty (safety lever designed for a Righty) with no 1911-style training. The P6 is somewhat pristine, and the double-stacked P228 is not.
>>If my somewhat worn P228 had only been designed as a Single stack, it would still be the main carry gun<<.
The mag. capacities (for me) have no influence on which of these are carried-if they are pretty easy to conceal, extremely reliable, and preferably 9mm.