Nice going Chowder. There is no rule of thumb with those speeds. It depends on the wind and currents and what they are doing that particular day. Trust the probe.
Rig your flies with 40 or 50 lb floro, then that won't happen to you.
Split, I'm going to get in the derby, even if I don't fish, to me its a very worthy cause, me being a musician and everything! lol
RR