I am sure that should be enough flow using the sizes you provided. I believe you are looking at 700gph per a 3/4" bulkhead. I am using herbie also 1.5 dual with gate valve, 1 inch emergency with no restriction. reeflo dart on a 2.5 split into 2 2in return with oneway valve. extremely quite, and lots of flow. One thing about herbie is if you use a filter sock you will have to adjust it when the filter sock slowly plugs up.
BTW I don't hear my Aqua illumination sols at all.
