I think the old trucks were hinged in three places because with just one the headlamps would obstruct opening the hood, problem is it's got to be at least one in the middle and jiggle opening it or go all the way with three.Yikes, I can see exactly why the bonnet lump would be a problem.
I have seen kit cars with a bonnet hinge on one side, but many also, like the one on my Marlin, which is a one piece you have to take off each time.
Can you not hinge it at the back somehow?
Vent is a problem with either option.
I think it'll look better with th three, bought em now anyway