I have a Gen 3 G22 with a RTF2 upper (the one with the gill serrations) but with a regular Gen 3 frame. I used the RTF2 frame for a racegun build and I don't want to part with it.
Has Warren Tactical sights installed plain black front and rear. Gun is in excellent condition with less than 200...
My son starting shooting 3 gun with me this past year as well. I was able to use it as an excuse to buy myself some new gear and pass down my old stuff.
As far as capacity goes, 8+1 is good 9+1 is better.
More chokes will give you more options. But a lot of people can get by with just one, either LM or IM could do it.