I would recommend a 30S over the 30, and I have had both. The 30S still allows you to use the 13 round 21/41 mags for a spare mag or at the range. The 30S has a little thinner slide and allows you to use holsters for a 19, which gives you a lot more holster options. It even fits G19 pocket holsters (yes, they make them). I pocket carry my 30S this way all the time when wearing jeans or cargo shorts. I use mine with 13 round mags without a spacer all the time and never have a problem with it feeding incorrectly or pinching me.
Get a 30S, carry with the 9 or 10 round mag, and carry 13 round mag as a spare.
Get a 30S, carry with the 9 or 10 round mag, and carry 13 round mag as a spare.