RE: wave sail size-ola,kevin?
Spanning the wind range from 20 up to 40 knots with just 2 sails including a 3.3 size and one 400 cm mast is quite a bit of a challenge...
For hardcore freeriding with wave gear, the maximum gap you can have between 2 wave sails size with minimal overlap is about 0.7-1 m2 in the smallest size and about 1-1.3 m2 in the largest size. With my 65 kg, the absolute minimalist quiver would be a 3.3 sail size (range +35 knots), a 4.2 (25-35 knots) and a 5.4 wave sail size (range 18-25 knots). If you extend these gap borders too much with just 2 sails, you will get "holes" in the overlap of your sail quiver. For me, a 4.7 sail size in addition to the 3.3 size would miss the mark completely: too small in the lower range and too large in the upper range (range 23-30 knots). It looks like your actual sail quiver of 3.3, 4.2 & 5.0 is actually not bad at all...
With regards to mast lenght selection, you might use a 370 cm mast with both the 3.3 & 4.2 sail size but you will require an additional mast for the 5.2-5.4 wave sail (a 400 or a 430 cm). Forget about using a long mast with a tiny sail : the bend curve and flex wouldn't fit with the sail cut. With too hard a mast, the leech doesn't open enough and this will severely cripple the sail performance in the upper wind range. Limiting the sail's wind range is precisely something you want to avoid.
Finally, you can't compare wave sails with race/slalom sail of the same size. The range of a wave sail size such as a 5.0 is the same as a 5.5 freeride sail or as a 6.0 race/slalom size. Therefore, your next slalom sail size after a wave 5.0-5.4 sail should be around 6.6-6.8 to par your slalom board as of 15 knots of wind. The bigger the slalom size, the larger the sail size gap can become with lighter and lighter wind. Again with my 65 kg, I have 6.6, 8.2 & 10.6 race/slalom sails to cover the 7-20 knots of wind range.