CPPSRB is fine, I just find DGM kinda sexy and use it on my TRC pool. I like the math behind it (non-hoppable, completely fair for all miners regardless of speed) and you just need to store 1 score per user, don't even need a share history.
I'll have to check though the math, I'm not familiar with DGM. I have a feeling that some hopping-proof methods become hoppable if you know when the proxypool server's going to be paid.
If you run a large public doge node in addition to your proxy, you might consider applying this patch:
https://github.com/forrestv/p2pool/pull/174We rolled it out on the whole Vertcoin network and it seems to work great.
Won't they still need to find a payable share to get into the share chain?