LifeReef Overflow Question

I have a Mag7 return pump, and about 4-5 feet of head loss....using the calculator it comes out to 400gph.

LifeReef has the nano overflow which has 3/4" drain and accommodates up to 400gph max. They also have the standard/slimline overflow which has 1" drain and accomodates up to 600gph max.

I was hoping to go with the standard/slimline overflow with 1" bulkhead drain to my 1" pvc drain piping. (And to accomodate for the case where my return pump might be pushing a bit more than the calculator calculated)

I have read many reviews on LifeReef overflows and the only issue I have read about is if you are not feeding enough flow through the overflow for what it is rated, and bubbles slowly form, potentially breaking siphon. All of these cases are resolved by person providing more flow or replacing the overflow with one with a smaller drain bulkhead....

My question is....For the people who own LifeReef 600gph standard/slimline overflow...

Do you believe these bubbles would develop with around 400-450gph? (or should that be sufficient flow through the unit)

I'd prefer to not have to go to smaller model and dial back the return pump.

The LifeReef website says it can handle all flow as small as it can be, but I'd feel a lot better hearing of experience and if anyone is running ~400pgh through the 600pgh unit without siphon breaking issues....

Thanks!