Unless I'm going to IWB "appendix' carry a smaller pistol, like the Glock 27, the only other location I'm comfortable with for IWB is 3 o'clock. If I carry any further back the grip will print when I lean over.
In the picture I'm carrying a Glock 30 IWB at 3 o'clock. Typically, I would wear a looser shirt like a plaid button up, not the solid polo style I've got on. I wore the solid polo because it readily prints the pistol grip, revealing any shortcomings in the carry package. If I lean over, as if getting a drink from a fountain, my rear pocket flaps print, the pistol doesn't.
The holster is a "modified" Blade-Tech Ultimate that I cut the sweat guard off and put adhesive sealant on the moving part. It's made to be tuckable, but I don't require that feature. With the holster adjusted to the cant I want, I tighten down the screws tight as they will go then apply the adhesive to keep it there. I like the adjustable cant and I like how it carries the pistol low.
For reference, I'm about 6'1 and 195 LB.
Others carry IWB at 3 o'clock?