A good holster and a true gun belt are key factors in carrying a handgun. Even with good equipment, sitting for an extended period of time can become uncomfortable. The positioning of the pistol has more to do with comfort while sitting than just about any other factor. The further aft of 3:00 o’clock you go, the more uncomfortable it will be. Another factor is how high or low does the holster carry your gun? As a general statement, the lower the gun is, the more likely the muzzle will hit the seat and push the gun up and likely into your ribs. A high-ride holster is less likely to so this. (Obviously, a shorter gun in a low-ride holster won’t do it either.)
When you get your Comp-Tac and gun belt, I think you will find carrying to be much more comfortable and secure. You will still have to try different carry positions for long periods of sitting. When my wife and I go to a movie, I usually carry a Commander rather than a Gov’t Model 1911 to avoid having the muzzle hit the seat. Also, I make sure the gun is at 3:00 o’clock to keep the back of the seat from pressing the grip into my back.
I hope this helps.
Chas.