Trying to get a mod finished and not having much luck in the hinge department.

Can anyone tell me whether your rear storage compartment hinges are stainless or aluminum?

I was looking for smaller butt hinges but think I'm going to have to go with a piano hinge instead, similar to what I've seen on newer boats like this.

Also looking for approximate dimensions of the flat hinge side that is anchored to the hull (height), and the L shape side that is anchored to the bottom of the sun deck cushion. I don't really want the hinge pin sticking out past the cushion if possible, but also don't want it binding up every time it is opened and closed.