This is a basic drawing for a springer, found on another web site. The prop as far as I am aware should be level with the deck, the springer likes diving without giving it a hand. If the batteries are set slightly back from centre the springer will run in a fairly level state, as long as you are not heavy handed with the throttle. If you give the springer full throttle it only does one thing, dive you do not have to worry then how level the deck is, just is it watertight
On my springer with the Pepsi can bridge, full throttle will put over an inch of water over the front of it and getting deeper, luckily my superstructure has a o ring seal on it. Some people have put a coaming in the front between the knees to stop some of the water, I tried it but felt it just trapped the water and helped the springer dive.
These are just my thoughts there are other builders out there, who might have other ideas.