If you really want to Jam or try this out, keep checking back frequently to catch people in the Jam Rooms. A pattern is finally starting to develop but OJS is still only 4 months old and there can be a Jam start happening litterally 1 minute after you leave the Jam rooms because it was empty. I've seen it time and time again. I've also seen 7-8 people in until 4-5 am PST. So for the most part, here is a general rule of thumb as of now:

Base your checkin times to 5-6 pm PST and figure there is a Jam in that time frame going to happen until 12 am. Your guaranteed a Jam this way and in fact, it gets pretty hectic in the Jam Rooms if everyone is hanging out in there. So maybe find someone to pull to another room.

There are waves of early rise Jams and afternoon Jams as well as very early morning Jams. Friday And Saturday seem to have picked up this last week but the pattern so far is Friday and Saturday have been pretty dead Cause of gigging or partying I figure. Hope to see this change and if everyone does their part and just keeps checking back in, this is going to ne awesome.