I'll offer a comment here, but it's a bit ancient on the scheme of things. Back in the early 90's I was pretty much exclusively using race sails down to 4.2.
While vacationing in Maui off Spreckelsville in Summer, I was sailing there, and up as far as Hookipa (from a Spreckelville launch), and the upwind ability of the race sails was notable. So, even though times are a bit different today, I think that mixing it up is quite possible. I'm not suggesting the combo is the ultimate kit, but as long as your fin is properly matched, the game is more open then many realize.