Guild Switch Question

Does anyone know if all the rules that apply to guild switching are published anywhere. I cannot seem to find the right words to search etc.

I know that players can no longer particiate in raids started before they joined, but beyond that I would like to know how long does a guild need to wait before launching a raid to make sure any new members can both participate and get rewards?

I am part of a guild alliance and would like to make sure members we move around to rebalance the alliance don't get locked out of rewards. I believe some of the anti-mercing changes were all stealth and not published.