I use the trickle trick as well. I've never been able to exactly match the return pump's flow so I opt to send some down the emergency rather than let the primary suck any air.

I shut my return off every week for my water change since my return compartment isn't large enough to keep it running. Upon restart I have to adjust the herbie every single time. Week to week tho it never needs tuning.

I've used the feed mode on my pump a few times now and other time shut it off for sh*ts and giggle and have not needed to play with gate at all

I don't trickle down the emerg and leve runs constant within a inch