Originally Posted by Roger
So, let's look at what is specified for your 10.0 m2 North Daytona.
At the time the Daytonas were designed, North was on a "minimum mast" program so they designed all of their sails (besides the top of the line Warp Race sails that only worked on top of the line Viper 100% carbon race masts) for only a couple of masts.
A 430 cm IMCS 21-23 and a 460 cm IMCS 24-26. For larger sails like your Daytona 10.0 North sold a CX (50 cm Carbon Extender) piece that you put under the 460 mast to extend it to 510 cm. So my guess (without some serious and detailed testing) would be that your 10.0 m2 North Daytona was really designed for a 510 cm semi "flex top" mast made up from the 460 cm IMCS 24-26 std. mast with the 50 cm CX extender under it.
Think your 490 IMCS 28-30 Yes 55% mast bends exactly the same as a 510 mast with a softer top?
So, since the sail was designed on the 460 mast + 50 cm CX
Thanks, this makes things way more clear now. A small correction, though, as you keep saying "460 + 50cm CX" - it is 490 actually. 490 + CX (not 460) _is_ the recommended mast length for a 10.0 NS Daytona 2007.
The other choice (marked as "OK", not "best") is 510 (I know, 490+50 is not 510).