Sides stays are pretty loose, as on reaches and downwinds the sail can keep shape as the loose rig gives to accomodate the sailshape.
I have been double blocking my main, but I am very aft raked.., besides the 10 hole, I also have the spreader wire attached by shackles. Eliminated side stay adjusters and just us shacles.
With stock Hobie sails you cannot sheet very tight. With after market you can sheet a lot tighter and not loose speed. Calvert sails seem to be able to point a little better than most after market sails.
Downwind head for the mark, but look back for puffs to get into. Tacking downwind rarely pays. That is why official Wave course try to all but eliminate the downwind leg -- boring! Rick