Sail size

Question
Hi!

Thanks for your advice on the Ezzy Free Ride 3 sail.
I am getting a Tabou Rocket 145 STD board  shortly .  So far, I have been using an oldish but still functional 5.9 sail and a new 8.5 Severne Focus  on a 190 lt Starboard Rio and I am now planning to buy an intermediate sail.  
Given the fact that the Rocket, at 8.4 kg  is very light (almost  1/2  the weight of the Rio  and much more lively ) and that I normally sail in light winds, I am debating whether, as an intermediate sail , I should buy a 7.0 mt sail  or if I could  go up as much as a 7.5, without risking to approach the overpowering range for my skill level, which is not advanced.  .
In other words, would a 7.5 help me in light winds without throwing me off control,  or would it unleash too much power for me to handle? In which case I should stick with a 7.0.
Certainly, for the wind-speed range I normally sail ,  I never felt overpowered, even with a 8.5 sail. But the Rio was very, very  heavy as compared to the Tabou Rocket !  
By the way, Ezzy advertise their freeride  sails as having an exceptionally wide wind range : with the proper tuning, they say, you can go up or down one one m2 from the nominal size. True or marketing spin? In the end should I go for a 7.0 or a 7.5 ? By the way, I weigh 79 Kg , about 173 lbs.

As usual, I'd appreciate your advise.

Thank you

Franco

Answer
Hey Franco,

The rule of thumb for sail size between sails is something like this; 4.5-6.0 ~ 1/2m2 between sails, 6.0 and up ~ 1m2 between sails. It used to be a bit different but with the sail range of newer sails, this is about what is suggested.

This being said, I would recommend going with a 7.0. With you having a 5.9 and then an 8.5, I feel that a 7.0 would fit nicely between the two. A 7.5 would be a bit far away from the 5.9 and too close to the 8.5. As for the Ezzy sails having great wind range, it is true and being true, it is a great marketing spin. I know that 7.0 to 8.5 seems like a large gap but the 8.5 should have a good enough range that when you have rigged for it's maximum upper wind range, that you would be really close to being able to rig down to the 7.0.

Hope this helps.
Keep on sailing,
Windlover