I usually measure about 5 to 10 cases out of the batch of brass I'm prepping, if I feel it's too long I'll trim the entire batch using a Lee cases length gauge. Puts it to SAAMI and I won't have to trim again for another 2 loadings. As far a crimps go, I use a moderate to heavy crimp on anything going in a tubular magazine and a light to moderate crimp on everything else with a cannelure ring. That seems to work for me.