So after making all the different pvc overflows i could find and never getting a great flow rate, I'm curious what would happen if i mimicked an overflow box out of pipe. 2 1.5" pipes capped at the bottom and then 2 3/4 inch pipes with a u bend at the top pvc cemented in and using a t joint on the output instead of a bulkhead. It seems so simple yet i haven't seen this done, is there a reason for that? am i overlooking a major flaw?