I tried a few off-the-shelf (retail) OWB holsters. No holster felt as good immediately upon putting it on, and the fit is only surpassed by the perfect retention followed by an easy draw. It took some time to get it, but it's worth it. The others have been returned. My Spara stays.
My next move will be to determine the variables in T1C AIWB holsters. I have confidence in the firm, and with the right decisions, I will have the two holsters I need for a variety of clothing and situations.