If memory serves, there's a good bit of info on hard dinghy; stowing, towing, swamping prevention, etc., in Bruce Bingham's The Sailor's Sketchbook.
A lot of the info on such, he Had to learn out of necessity, as he spent a good bit of time living on, & cruising a 20' Pacific Seacraft
Plus, there's a lot of other neat & useful info in it, along with drawn illustrations of such. Hence the book's name.
Also, you might be able to shoehorn a nesting dink like the PT11 http://ptwatercraft.com/ptwatercraft/PT11Home.html
, Danny Greene's Chameleon, or Dave Gerr's Nester onto your boat
, although it'd be tight. But with a little work
, the latter 2 dinks can be scaled down a bit, prior to building. Not so much with the PT11 as it's only a kit for now.
Plus, a "Spreader Bar" (perhaps not exactly the technically correct term) might make onloading, & offloading your dink a lot easier. Ditto on a well thought out lifting bridle
PS: You needn't rule
just because your dink's longer than your boat's transom is wide. I'd think that it'd be doable so long as your dingy isn't longer than your boat's beam (length).