Beananimal Overflow - Ball or Gate Valve?

[syncro]

Can you use a smaller diameter drain line to get a cheaper gate vavlue? Full siphon drains a surprising amount of water compared to a partial siphon.

I suspect you can by with a ball value it will just mean a lot more fiddling because of the overshoot scubasteve mentions. I find I need to make tiny adjustments - a few degrees turn on a gate value that requires multiple full turns to fully open or close.