Check out,
http://www.loftsails.com/kam_pages/1/e/7.php..now even if you don't have the 2008 sail, there are _link_s at the bottom to previous years product. Find yours and you should be able to find the manufactureres recommended specs.
I'd agree too with the comments so far, If you can get a samller mast and an extension to bring it to the correct length then you in theory carry less kit. But you need to ensure the curvature (IMCS) of the mast is correct (or roughly the same) and that if you buy a big extention pay good money fo it 'cos the cheap one can be very heavy.
Ern.
Shawn, got ya new bike yet ?