Well there's obviously a mistake in X-Type specs: the 6.0 has longer boom than the 6.6 !! But a 6.6 may do the job, depending on your weight and skills.
Another option is Naish Sprint 2008 (2009 version has shorter boom and rigs on a 4.30 mast). These are excellent sails up to ~20 Knts.
Last edited by Farlo; 11th September 2009 at 04:31 PM.