One last word, if you state you can righten the boat, please let us know, what is your weight and if you use any aids, because this is an other very important criterium to buy or not buy.
Of course Andrews answer takes precedence, but I may add some interesting viewpoints. I also have a piece of Capricorn mast section at home, the infusion mast is practically the same.
If we lengthen the current lightweight F16 mast to the same length as the US F17's (which may not be the same as the EU F17's when going on the dealor specs). Then you'll need about 8 kg additional righting weight.
If we made the 8.5 mtr long F16 mast from cutting down the Capricorn F18 mast then we'll need 7 kg additional righting weight.
If we were to use the full length capricorn F18 mast on the F16 then we would need 17 kg more righting weight.
Interestingly the difference in weight per meter between the current F16 superwing and the Cap F18 wingmast is only 200 grams per meter. Still, when taken over a full length mast then weight differences quickly add up to additional required righting moments.
To show this point more clearly just image that we add only 0.5 mtr of mast height to our F16's. At 1.65 kg / meter this comes out at only 0.825 kg added mast weight. Negligiable you think ? Not really ! As it is positioned at about 8.75 mtr away from the fullcrum this little section alone already adds over 7 kg additional required righting moment. That is significant difference !
We all have encountered the magnitude of this added weight when we had only a little water inside the mast.
Wouter
