There are many aftermarket ambi safety choices for 1911s - many are 'drop in ' or near so. As Griz mentioned it's a very easy job for a local gunsmith as well.This is a small job that a decent gunsmith can complete while you are standing there (assuming you have the new switch on hand). I’m all for the classics and love my 1911 above any and all 9mm types.
1911s require good magazines. Wilson 47D is my go-to for 8 round magazines. They make 7 round flush fit mags as well. Epic reliability. When MARSOC ran 1911s, Wilson mags were the only choice for Marine armorers.