If you don't have any data on the torque curve, you may start at 4500RPM and make a few launches (AT THE TRACK) then change the rpm 200 higher, make a few launches then 200 lower than 4500RPM and make a few launches. It would be nice if you did this all on the same day at the track, and in the same lane. There is not a correct answer for your question, your car and combination needs to decide, and you need to explore each choice and look for a trend by time slip to the 60'.
Food for thought..........