Usually we wait until after Thunder Over Louisville...sunset right now is at about 8:15, we usually wait until it's at least 8:30 which will be around April 26th and on.
We try to get in at least 3 hours of fishing (6 to 9), right now it's a little tough to do that unless you takeoff at 5 or 5:30 which is difficult for most to get off work in time, grab the boat, and get to Cox.
If you wanted to, you could tentativley plan on the first one being April 25th, and go from 6 to 9 - Civil Twilight for the 25th ends at 8:57 which is what I usually go by for the ending time of the tournament.
Tentative Schedule:
April 25th
May 9th
May 23rd
June 6th
June 20th
June 27th
July 11th
July 25th
August 8th
August 22nd