Check the jump out, watch other people hit it, even ask people who have already hit it. If you asked me, I would tell you if you should go slower or faster than usual and if it has more pop or distance.
As for sending 3's, after 4 or 5 hits you will know your speed. Going into the jump, your mind will play tricks with you- telling you to go slower or sometimes faster but don't listen to it. You have hit the jump before with the right amount of speed. Do it again.