Also, in regard to the down haul fix I will probably stay 8:1 but will go the Nacra way and fit check blocks to the sail itself for two of the purchase so I can exit the RF5s the right way up or go to standing blocks and out to the hull to a cam cleat like the F18s.
If you are getting block to block it won't matter what purchase gets it there.

Whatever I do, I will post photos for a crit.