On my 40B I use something similar to the PF-1000. I put a standpipe in one of the outlets as an emergency overflow. There are two separate drains from the overflow box, one has a gate valve (don't use a ball valve - too hard to adjust) I use it to maintain the level in the box (keeps things very quiet), the other (from standpipe) is a straight to the sump. This setup is only single redundancy, but I've been using it for many years and never had an overflow. My return pump is a Mag-9, that also drives a GFO & carbon reactor.
Whatever you choose, I strongly suggest some form of redundancy.