I have read your early 80-85l wave twin test and just a quick question regarding the Quatro81. You say that it isn't too quick on the plane. Is this in comparison to the others on test or in general. I am looking for a new wave board pretty soon and the quatro is one of my strong considerations. I am 77 kg and want it as my main wave board with a quiver of 5.7, 5.0 and 4.2. Mainly sail at Rhosneigr, but also lots of other wave spots from dtl to on shore to flat water - just what the day throws at you! i do have a free ride board for 5.7 upwards and a small wave board for 4.2-3.7.
I'm 86kg and use this board as my only wave board with 5.3, 4.7 and 4.2 sails. For my weight it doesn't like using anything bigger than a 5.3....I tried it with a 5.6 but it struggled. The board does feel small when using it but my friend who is your weight uses it as his lighter wind wave board.
In terms of euro/onshore waves, it does work and has reasonable speed for jumping but not as well as say the new tempo. I find it not the most comfortable to sail in a straight line or in choppy conditions as it prefers to be on a nice wave. Once on a decent wave though it is amazing, one of the best!
Once on a wave the sail size isn't too much of issue I find. It was mainly when sailing along that I found the 5.6 was overpowering the board a bit.....it started going sideways as much as it was forwards. Perhaps some bigger fins would help? It's perfect with a 5.3 or a 4.7 though so if you don't plan to use any bigger than 5.3 then I wouldn't worry