Pro gives more drops, but is significantly harder to complete. only MCS+ clubs can do them effectively
I think Pro parties were released before BC was 3mcs, and I think the earliest I was able to hit a pro was at 200kcs, so rlly any full club with 500kcs players should be able to do a pro.
Idk about how the parties are now, but before rs partners you pretty much only used pots. I was 22kcs and able to hit a few times in an easy pro (Didn't have much help with misc and tuts at the time, I was a true social noob). So if you're planning to hit a pro try your luck, but they are a bit harder!