IMO, the airborne 7'10" 31.5" is far out too much confortable to me but is a good starter as shortSUP. Or can be a good shortSUP for +100kg guy...
IMO:ShortSUP go around 28" for my weight of 75Kg with a bit more liters than weight.
Short SUP dimensions should be in keeping with SUPer weight/ liters .The dimensions: width,, length been involved from equal ratio weight/liters.
As i've been surfing with teeny board( 5'9" < 19") about 20 years ago, I got use to enter the wave with strong paddle but a good wave placement is lot more efficient .
So this is what i do now with shortSUP, good wave choice and right placement is the key to succeed taking off and get some G from a carving bottom turn on a clean face.
IMO, while surfing paddle is made to carve wide shortboards which are these shortSUPs. Just paddle back laying on chin on the paddle relaxing my old surfer's neck, step on the board on the back of the first wave passing by the set and paddle for a ride on one of the next ones.