PS. don't remove the entire loaded chamber indicator, as you don't want that opening in the frame, in case if an out of battery discharge.
There's a much bigger hole in the other side, you know. Removing the LCI does nothing to reduce actual safety, and can in some cases enhance reliability by removing a obstacle to proper feeding or ejection.
Removing the magazine interlock removes the need to have any magazines present for cleaning, which involves multiple trigger manipulations ... seems more safe to me but some would disagree.
The internal lock is useless but non-offensive ... just ignore it.
The US-style magazine release is nice, I can work with a heel release but I prefer the button. (actually I prefer the Walther/HK flipper under the trigger, but the only .22 with that is the P22, which has limited usefulness unless you want a trainer for a P99/pk380/PPS/SW99 type gun.
I have and like two Ruger mkIII pistols, they're great guns with few problems if you understand the internal workings. I wouldn't turn down a mkII, though.
Either model will get good support from Ruger if anything does manage to go wrong, and either model is tough enough to buy used with no worries so long as someone hasn't been into them with a Dremel or something awful like that.
Any rental range will have a mkII or mkIII, go try one out, I can't pick a gun for you, do it yourself by actually shooting one or twelve.