I was taught in 1981 to grip the 1911 so your thumb is on top of the safety.I asked because a friend has a custom 1911 he does NOT shoot with his thumb on the safety. While out shooting a few weeks ago he kept having problems with accidentally turning the safety on.
The safety on his gun is very light to me. A very very expensive custom 1911, but it got me to thinking how easy it would be to have that happen especially in a high stress shooting. Could be the gun needs to go back and that was my first suggestion. The second suggestion was change your grip. I am sure not the authority, but I have had several 1911 shooting courses and have always been taught thumb on top of safety.
Thanks
Carl