bluey
You should ude all ranges of motion from pin heights to boards. But you cant work at your sticking point all the time. Work on it for two weeks then change. Use 3-5 reps to practice getting through that point. You could also take a max a few inches below your max and then hit a higher volume at the sticking point. Only do things for a couple weeks then change then come back for a max a few weeks later. There are tons of other things you can do depending on what you have available. I dont know what level you are so just train smart. Good luck.
bluey,
I cant believe I left this part out. Make sure you are doing enough quality assistance exercises for the tris, lats, and upper back. Doing this will help tremendously.
Personally find Board presses, floor presses are better than pin presses for training the bench. Pin presses (except for very small ROM 4-6") stress my shoulders and elbows too much.