If you are a dev, your first priority is to produce and work on content, not join test sessions. We have no set limit of work hours that you must devote to FH2 (that would be stupid). Devs give what they can. Some weeks, a lot of work gets done, other weeks not so much. In fact, we've had a few devs recently come back after a period of 6+ months of inactivity.
If you think you can help out, apply. We will try and find a place for you.