Vfrpilotpb - I spoke to my passenger last night, who reckoned that the helicopters are considerably less than a runway's width (23m) away from the runway. Subtract the distance to the rotor tips, and that's too close in my book.
I appreciate what you're saying about mixed ops, and I could see it might work on a field with full ATC but as the field is air/ground only you are relying on the other pilot(s) seeing you - if he's a low hours student trying to hover his attention may well understandably be elsewhere.