On my gas powered v box the gate is open 1"
On the smith about 2" because the apron chain runs slower. Actually leaving right now, to presalt in case of flash freeze due to cold road temps and rain/sleet coming in one hour.
Our gas drive Vee box REALLY puts out material. I have found (only one use so far) that I have the gate shut as far as possible, maybe a 1" gap, and I am running just above idle unless it's a wide open lot where I can sling the material quite a ways without salting the lawn.