Yup, I've got an R.

I don't do well - but that's because the other guys are better than me and not because of the handicap! I'm sure I'd do better doublehanded but I enjoy singlehanding and it's a lot less hassle than having to find someone light for the front of the boat!

704 is probably about right - I did a quick calculation and came up with 702 (sorry!). You're talking about a difference of less than 1% so in reality it probably doesn't matter very much - one poor tack a race or so! Perhaps most important thing is the difference between your handicap and the handicaps of other fast cats you're going to race against. Might be easiest if you do a comparison between what their PY and SCHRS handicaps are. For example, Stealth F16 SCHRS is 1.02. Spitfire is 1.04. Hurricane 5.9 and F18 are 1.01. So, if there are any of those at your club you ought to get a PY about 1% more than a Hurrican/F18 or about 2% less than a Spit. Probably not so accurate if you have to compare against boats like Dart 18 or Hobie 16 though.