Tours Topper?

[ernie]

I’m thinking of designing and building a 12 ish foot sharpie to be light enough to carry on top of a Ford Tours, and provide comfortable semi dry sailing for two. This boat will probably have 4’ or 4’6” maximum beam. I’m thinking of a cat yawl type rig; Bolger 59 main, smaller sprit mizzen offset to stbd, stepped on transom with a boomkin.
Questions:
Should I use a minimal bow transom? To move buoyancy forward.
Should I make the main bigger? Remember this boat is skinny.
Is it worthwhile to have a second place to step the main further aft to sail on one mast in more wind or just for convince? I vaguely remember pictures or plans of old working shapers with this feature.
Leeboards, daggerboard or centerboard?
If the mizzen and rudder are both attached at the transom is it a ketch or a yawl?