51,
you can use this google docs sheet for warm-ups:
https://docs.google.com/spreadsheet/...thkey=CPfCneMN
Personally I like a single around 10-15 lbs away from my work set like you for the squat.
Icing is always a good idea. Is the pain sharp? If so, wait until it dulls then start doing the rehab prescribed on the SS forums (think it's in a sticky). A bit hard to use compression on your glutes, so that won't work...
ETA: not so sure SMR is a good idea if the pain is a bit bad, but after it's subsided then sure.