I had an interesting session yesterday. We were slightly optimistic. Wind was 20-25 knots with small waves -- forecasts were 25-30 but the hour was not very precise. We had to go upwind to reach a cleaner playground so I took the Wave 8.5 (wind range being very large) and a smaller board (Stretch 5'11).
When we arrived, wind kept in the low twenties for some time and then increased to 25-30 knots (my co-rider was on a Sonic 2 11m ... ouch!
). I had more than enough wind but the good news is that I had no difficulty for surfing even in that wind range (note that I kite with foils since 2002 so there are some flying skills involved). Wind was nearly completely side where we were and I could go fully downwind on the first bottom, with the kite crossing the wind window without being ejected from the surfboard. I could even loop the kite while surfing (high in the wind window) to replace it for surfing. I still have more upper wind range available for safety. In 25-30, I can still surf with a kite (but I definitely could be on a 4.5). I had the Wave 8.5 in strong winds before but this time I have the wind statistics for the session as an objective measure (wind was dry).
This means that the Wave 8.5 can definitely be paired with the Wave 4.5 for travel (my weight is 63kg). I still need to fly more the Wave 12.5 to get a clearer idea of the wind range I have with 4.5 / 8.5 / 12.5 (even if the 12.5 was primarily for snowkiting). Upper wind range is 45 knots while being safe, this I know now