Short answers as i'm on my phone.

Moving the beam back will effect how you sail the boat. You'll need to stand well forward up wind so don't go crazy. new hulls have different bouyancy distrubution to suit.

To determine appropriae hull cant:

cant=1/2*(tan(-1)(hull draft/hull seperation)

To set parallel mark points on the bow and transom at desired upwind trim before removing existing beams. Remember if you cant get them perfect, toe in is better than toe out.