I'm not fully aware of how you want to carry a full size pistol like a HK or a ParaUSA type but here are a few suggestions;
For concealment & regular carry(low threat areas where you may sit a lot), a shoulder holster may be a smart move.
I used a Aker Comfort-Flex shoulder rig for my Beretta 96D. It worked great. The angled style carry does well. Let gravity be your friend,
Other top holster & gear makers include: Galco Miami Classic II, Lawman LeatherGoods STU, Kirkpatrick Leather, Bianchi-intl, Alessi, DelFatti, DeSantis.
Call the shop or firm first to make sure they can send the correct fit. Some designs may change or have minor modifications then not fit your pistol.
There are decent cross-draw holsters out there. I'd get a horsehide or Kydex type. Or the holster style that can be adjusted or converted for cant/height.
Greg Kramer, El Paso Saddlery, Milt Sparks, Don Hume, HighNoon Holsters or Blade-Tech may have a rig you like.