I've taken them both ways. Prior to training and spaced out evenly. I saw no difference in overall results, but prior to training seemed to help the workout.
I wouldn't be suprised if it was just a mental boost though.
I do take letrozol w/ my dbol and it keeps the bloat away. If you do take the full dose prior to training, take the letrozol then also.
My 2 cents only.