thank you Roger and Haggar,
I will try your recommandations.
About the last questions you have, I can't try the F2 fins on my new Kode 103, as F2 is with powerbox fin and Kode 103 with US box.
Now I only hesitate to make my first trials (again) with 3 or 4 straps in the back position ????!!!
I ask myself that due to the width of the Kode, the 3 straps position (internal) could be more for "expert wave level or freestyle" ?
Perhaps for my medium level a 4 straps position (external one) is better ?
what do you think ?