That's the main question. The rest below is an explanation as to why I'm asking that question.
I'm running Clintar's pool software for my private pool. I've noticed that no matter what port I connect to, the difficulty always ratchets up to a level where my low-end miners can't submit shares. The pool eventually and slowly adjusts their difficulty back down to where the miner can submit a share, but then it ratchets back up again, resulting in miners that can seldom submit shares.
So, I set the maxDiff of the pool to 7000 and now my miners can submit shares 1-3 times each minute. But will having a relatively low pool difficulty hurt my pool's chances of solving a block?
Follow-up question: What if I add a GPU later and keep the pool difficulty level at 7000, which is low for a GPU. Will that negatively affect the miner's performance, or more importantly, my pool's ability to solve a block?