Interestingly, this topic came up at the LQS this week among several of us. We did some checking out of a BOM the LQS has going on that uses 6" blocks that are complex--we decided that as long as you did not plan on SID the whole blocks, that pressing to one side works just fine when the block doesn't have lots of seams but when it does, pressing them open. The owner of the LQS uses something called a pressing stick that allows her to do this easily without getting burnt fingers!