Hi Alan - not being a naval architect, I cannot speak to most of these considerations, but I bet somebody else will!
I can offer you a bit of info on a couple items.
Off setting the boards from centerline seems common to keep the trunks from being in the middle of the living spaces. The
Catana boards are placed
outboard such that the
outboard side of the trunks coincides with the outboard edge of the hulls. It seems they could be "justified" to the inboard sides as well. This also has the advantage of not having the opening for the boards right at the bottom of the hulls if the
boat can be beached. I've seen some boards angled a bit off vertical athwartships apparently to make the trunks conform to the outboard angle of the hulls.
Designing the trunks to be stronger than the boards seems intuitive - sacrifice the board instead of the
hull in the event of
collision.
The lifting mechanisms I've seen are remarkably similar, although I certainly haven't seen them all. A line attached in some manner low on the board runs vertically up the trunk in a slot, around a block below
deck which is routed through a chase to a
winch aft.
Rope clutch to hold it up. To raise the board higher or remove it you have to
lift it from the top. Drop by gravity. The
Catana boards have holes in the bottom so they flood with
water so they won't float in the trunks.
Hope this helps,
Dave