As sold on soundproofing.org, RC-1 are 'hat' channels, 1" depth. RC-2 channels are deeper, something like 2 1/4" - you can check on their site. RC-2's simply lower your ceiling more, allowing you to get more insulation in the joist cavities.
If you're going to use the SSP clips, don't worry about differences in performance. It is an excellent system and, as you said, you only need moderate soundproofing (not a recording studio, etc.) any differences will be minor and unnoticeable, if you plan on using 2 layers of drywall on the ceiling (recommended).
Just remember to keep your field joints tight (but seal them beforehand) and leave 1/8" - 1/4" at the edges and do some good sealing there before you mud and tape. Also, it might be a good idea to use an 'old work' electrical box for the light(s) instead of a conventional one, rigidly attached to the joists. It's more work trying to get the thing centered, but it can otherwise transfer a lot of sound energy. Also, seal up the holes in the box and the gap around it too.
If you've done the ceiling and find that the walls are transferring a lot of noise, you can tear off the drywall and use the same system (SSP clips + hat channels + double drywall) there too. I think you'll get an STC (roughly) of 64, which is excellent. It'll be a quiet place.
Keep your quality control high and I think you'll be pleased with the results.