Old question about spinnakers and racing
You might look at some testing that US Sailing did on this subject;
You can also look at http://www.phrfne.org/adj.htm
to see how PHRF adjusts for asymmetrics.
Subject to getting better spot-on advice on this board, I recommend you work this question over with the hot-shot sailmakers who will be eager to sell you sails for your new boat - they are folks likely have seen both alternatives in good use and I suspect this question doesn''t have pat answer (but what dooes with sailboats...).