Sail sizes for st 126 and carve 145

[Nacho Checa]

Hi all:

I have a stype 126 . Weight 75 k. I'm saliling the most of times with 13-16 knots, and less times 20 -25.
I would like to renew the sails (currently I have 5,8(new) 6,8 and 8,5). I'm thinking to have 5,8 and 7,5 only, but I don't know if it's enough this range of sails and sizes for my board? Do I need other sail between 5,8 and 7,5?

Thank you very much in advance