I made my self a G10 fin for windsurfer and used single flute Carbide bit for roughing, same bit I use for aluminium, and twin flute carbide ballnose for finish. Both easily handled and gave nice finish.
This stuff is quite abrasive so if was cutting lots of it then think I'd look at the Diamond coated Micro grain Carbide which are better suited to composites has think it would workout cheaper in long run.?