I've been shooting LT-32 quite a bit in the 6PPC, and I found that CCI450 primers gave me the best groups. The Hodgdon manual lists 23.1grs as max with a 55gr Hornady bullet, so you still have some room to go. Personally, I don't even get the chronograph out until I have nailed down the primer, powder charge, and seating depth a load shoots best with. I'm not going to go changing a load just to make the numbers on a chrono look pretty.

"Give a lazy man the toughest job, and he will find the easiest way to do it"