AS stated you will be constricted by your magazine length. Also your new are willing to beat your eye sight on your OCL as measured to the lands? When you are 100% sure of the actual OCL I would suggest working up your max load at 0.020" of the lands if the magazine permits it and then working back to a shorter OCL by 0.005" or even 0.010" incraments too find the OCL thats give best accuacy.

I bought a LEE hand press just so I could load my best load for accuacy at a longer OCL and than at the range could shorten three rounds shoot them shorten three more at the next shorter OCL and so on till the group started to open back up. I stop there with the data in hand and the remaining ammo could then be shortend to the best OCL for more shooting.