Well I would experiment by switching the tabs around as described here: http://californiaccw.org/posts/list/793.page#9736
. I found it helped to conceal better, but I don't have your body type. I would also call Comp-tac and ask for JB, their General Manager. He indicated to me that they have some heavier guys there at the shop who carry in a CTAC. He may be able to give you some practical advice.
I performed the mod to my CTAC yesterday per the instructions and photos shown. It did seem to help in the comfort zone, but I'm not sure it's "the best that can be", so I plan to pursue it more.
It appears that the leather tabs could easily be replaced with new tabs, custom shaped and fit to raise, lower or cant the holster to specific personal needs. I will be hitting the hobby shops this week to get some replacement leather.
I've already been to the local hardware store and bought some new screws and T-nuts, in stainless steel - they didn't have the exact screws as came on the CTAC. I got longer screws since the originals, including the tension screws, seem a bit short. Also got the moleskin! Tough catching one here in South Texas though - most drowned in the past month of rain!
Anyone else install new leather tabs in this way?