The Springfiled Armory alloy frame officers model in the picture weighs in at 26.6 ounces WITH an empty magazine. of course besides being light its also very flat and the shorter grip and barrel make it a very comfy carry.
it has ambi safety but they are tactical safeties and do not protrude outward.
I also carry the Para LTC commander (also an alloy) often when in the 1911 carry mode, with a empty mag it weighs in at 28.5 ounces.
course the grip is longer as it takes full sized 1911 mags but it also has the flatter tac safety as well..
the only 1911 that the safeties really ate into my side was /is the PT1911 with them big old bat wing safeties, I have changed a couple out to tact safeties for that reason.