I do ours at 165 degrees for as long as it takes to get to the consistency you want. Spray your trays with oil or you'll be hating life, even with spray they may still stick.
It's a pretty tedious operation when done at scale. A good pitter that can do 5-6 at a time saves a bunch of effort.
Pick, rinse, pit, cut in half, arrange on tray, repeat.