I've had a full-size Springfield Loaded for a couple months now.  Whenever I've taken it on a range session where I fire more than 100 rounds, I eventually develop an abrasion cut on my firing hand at the base of the thumb.  Relative the handgun, it's on or about the rear edge of the thumb safety and frame.  Since it makes shooting uncomfortable, and I've never heard other 1911 users who've experienced it, I'd like to see if I could avoid it in the future.

Any ideas of what might be the root cause of this?  Upon inspection, the edges of the handgun do not feel obviously sharp, so I figure it is more likely to be a problem with technique.

If it is on the web of the hand between the thump and finger, then yes, I have experienced that.  On my TRS, it never hurts.  On my Kimber Custom, after about 100 rounds, it starts hurting for some reason.  

Shooting Kimbers with the stock thumb safety is uncomfortable for me. But the safety on Springfield guns are well contoured. Rub the transition from the grip safety to the thumb safety. It should be very smooth.