Just wondering if anyone has done trials on board length / speed

eg same paddler, same conditions same, same distance

11'0 surf style board
12'6 race board
14'0 race board
17'0 race board

So if I was currently paddling an 11'0 surf style I could figure out how much faster (km/h or %) I could go if using each of the different boards? I understand that board width, nose shape, weight all come into play as well but just looking for averages.

mmmm this is a hard one too much length with too much speed will not go well,unless appropriate training systems are in place. i would suggest to start with a mild stroke then ease into it,working your way to a optimum pace then finish strong...should be a gold medal performance. for those with shorter boards do as you please

Oh dear

Find a style, shape and size that suits you. Ive paddled a few boards that are popular boards, but i hated it.

When i finally bought a board I could have gone for a 14 (bettter DWer) but i went for a 12'6.
I find it nicer to paddle, feels goods on runners and when racing the competition is much closer in the 12'6 category.

Its also easier to transport, fits in my storage room and is good for cruising on small surf days.

As everyone says tho, try as many as you can.
There is plenty of different shapes out there.