I've been appendix carrying a SW Shield in a holstereo not designed for AIWB for the last 9 months or so, and there is no problem for me. I've carried a full size 1911 IWB for several years with no issues. My dress and body type make it a non issue.
To give you an idea, I'm 5'8, 200 pounds, stocky, fit (I power lift for fun), with broad shoulders. I wear button downs loose in the front when I'm dressed casual, and have concealed a 5" 2011 AIWB once or twice.
It's the weight, cheap replacement cost, and 19+1 capacity that make me want to carry the P09, and appendix has proven viable for me. Personal record with my shield on a modified bill drill (5 yards) was 1.81. I like appendix a lot. Hope that filled you in a bit. AIWB is not for everyone, though, for sure.