Hi Kenzzo, that sounds good yes, why not, 42 I think should be enough, with a bit more upright angle. Straps outboard and move the mast track a bit back from centre, lift up and push down on rails when riding to leverage the board up onto the fin and then hold it up on the rail slightly, reducing the wet surface while riding...should help quite a bit to get more speed.
or go for a Blast 130 if you want to go faster/Jag 125?