camo hosk said...I lived amongst some of the best waves in the world as you do I wouldn't be to concerned about flat water sup speed

Actually, training for flat water paddling can help you a lot in waves. Jut don't bother with the racing boards, just use your tippiest surf SUP and try to train until you are able to sustain a steady speed for an hour. You will find there is some "wall" at around 10mn where you feel exhausted and think you need some rest. Just train to be able to paddle for more than 10mn and should be able to paddle for hours... I can sustain 6.5km/h for an hour on a 9' now but before specific training I couldn't paddle more than 10mn without some rest.
Also it is a great way to enjoy flat water paddling with the familly. My daughters could enjoy a leisury pace on their 9' while I had an intense workout following them on my 6'8" :-) making 10km trips around the local islands a summer on my pointed-nose 7'10" helped me immensely.