I get the impression that single handers in general get hit pretty hard by the SCHRS. That's probably particularly true of boats with spinnakers where any boatspeed advantage over a an equivalent double hander will offset by hoists/drops being slower.

The Stealth R was easy - at least from a handicap point of view. The rating was 1.03 either way. That obviously isn't the case now that the main is bigger and the jib smaller in the F16 evolution. If you're adjusting the handicap to give this guy a "fair" handicap (which is what it's all about after all) then I'd go for 1.01 and see how he does, adjusting it if it looks wrong once you see some results.