Hi there,

1) if you have a boomless design, it has an effect. More rake = flatter sail = strong wind trim. With boom, effect is smaller or disappears.
2) I guess the reason why H16 use toe in is the non symmetric wake of the H16 hulls, which are as well not symmetric. If you have symmetric hulls, I don't see a reason for toe in.
3) in most cases: one hull just kissing the water
4) no rule of thumb available, nut let all your tell tales fly could be a good starting point.

Cheers,

Klaus