What you want is:
- an ultralight board, so that turning from the rear stays nimble. My 9'0" weights 6.8kg with the pad.
(I hunted a 2nd hand Gong Zero made at a specific time where they were fragile but ultralight)
- a pulled-in nose, both for paddling speed and early wave entry, less wing weight, and not catching a rail in turns.
The Infinity new deal has such a nose
- a tail as big as possible (wide and thick), depending on the strength of your rear leg to push on it.
this way you can take off of the smallest of bumps.
Gong "Moblog" was such a concept: a longboard SUP with the powerful tail of a small wave fish (The Gong Mob: hence Mob + Log = Moblog).
www.gong-galaxy.com/blogs/magazine/gear-surfoil-allvator-availability-9309 I had one, but I wasn't powerful enough in my rear leg to really master it, and I have the paddling stamina and technique to manage short SUPs anyways.
But as you can see, Gong has discontinued it, and not a lot of boards have this shape because it is
quite specialized, most shapers now use a pulled-in tail for control when waves are not tiny.
I guess rear foot surfers tend more to the short & fat solution, such as the Infinity Escape Pod, Gong Mob, etc...