I always find these sorts of stats interesting.
I started using a GPS whilst sailing in August 2004. I have logged 90% of my sessions since then noting the equipment I used. In that time the equipment ranges from formula board with 11.6m sail down to 44cm wide speed board at 5.0m sail ... and everything in between.
In 246 sessions I have averaged the following:
Average sail size used - 7.0m
Average wind speed - 17.6knots
Average fin size used - 35.83cm
Average board width - 63.66cm
Max speed achieved - 45.43 knots (2 sec)
Total Distance sailed - 11,032.29km
Average efficiency - 1.93 (*)
(*) average efficiency is a bit sketchy. I've divided my max speed in knots by the max wind speed to give this figure. There are many other variables, but this is still an interesting calculation. In light wind (iS131 + 8.3 Koncept with 50cm Venom) the 'efficiency' can be staggering. In strong wind with 4.7m Kult on Kode 86 the 'efficiency' is almost break-even, i.e. 30 knots of wind with 30 knots of board speed.
If I was to ever get sick of all my gear and just get one board and one rig, then theoretically I could just use the stats above to get the perfect fit.
I just like my toys too much ...