I can speak only from my own personal experience. I craft gun belts and holsters, and thankfully, have been able to experiment and craft several different styles of AIWB and pocket holsters for both my 3 inch and 2 inch hammerless SP101's, settling on what works best for me. My AIWB holsters all use spring steel clips to secure them to my belts. In 20 years I've learned that for me, the 3 inch serves better AIWB than the 2 inch. My 2 inch version carried AIWB tends to rotate with movement when carried that way, while the 3 inch barrel just seems to anchor the longer SP101 in position when AIWB. The 2 inch hammerless SP101 is hands down my best choice though when carrying in CAN and have experimented carrying my 3 inch in a pocket holster but some pockets aren't deep enough to conceal the grip butt.
Your selection will depend of course on your build ad lifestyle.
Don