hey Greeny,
I decided to go for the severne S1's, the 5.7 fits on the 400 skinny mast with a long ext. they might recommend a 430 but the 400 seems to work for me. I think for the ezzy's you need three half mast length pieces to suit that sail range.
The boom is a 135 to 195cm autima wave, carbon - I think the 5.7 is 192cm so just fits. The last autima carbon I had laste 2 grueling years. This would be less for the heavy people. The aeron boom is only 185 long fully extended so that didnt work for the 5.7. The aeron may indeed extend out to the 192 but for the price I wasnt going to be the test bunny. The sales people suggested two booms which I thought aaaaagh no thanks I'll go the autima.
the board is a 75L evo 07 model and suits my 75Kg weight. The board is sort of an allrounder but still works like a surfboard in good waves. I would like a 90L coasty board with a 7.5m2 and maybe a 69L goya wave board but, hey, when you throw in a kite and a surfboard quiver Ive overloaded the shed and used up all the leave passes. I try and live a balanced lifestyle here

The kite fills in the 14-18knot days when the 5.7 is just a little undercooked.
I used to go 4.2, 4.7 and 5.3 but found wanting the bigger sail on those lighter days when there seemed to be the swell. Nothing worse than watching people plane past and steal that wave youve been eyeing off while you dog it in to the lineup! I think with the newer sails the 4.2, 5 and 5.7 works but sometimes when its 4.7 or 4.5 its really handy to have something that size.
cheers
Poida