Options that I would have chosen:
1. Add internal overflows and build standpipes
2. redesign the filtrations system
3. Get rid of canister and look into Wet/dry,sump, or fuge.
4. Plug bulkheads and use external overflow
5. don't understand your system.
I know your question is there, but your poll....well really has no substance to it.
It almost sound like want to do something new to redesign, have you formulated any ideas on what you would like to do or am I off base here.
I think we have disscused before that although your system is different, it is working. so my question to you is What would you like to do?
Thomas