I have a large genoa made by Westsail; Luff 41'2" Foot 25'10" Leech 39'2"
It makes all the difference for sailing to windward in winds under 15kts. Off the wind we could carry it in up to 18-20kts. On anything fatter than a close reach we can add the stays'l to give us about another half kt in boat speed. Here's a clip http://www.youtube.com/watch?v=OGVswlhZjLA
I have the quick-release forestay and use it if we're tacking alot, but if I only have to tack once or twice, and feeling lazy can get that genoa through the slot with some help from the wind. The super yankee dimensions might be what you're looking for. Aaron compiled a list of sail dimensions and it might be somewhere on this site. Aaron?
My super yankee is a little smaller than Kern's, but the cut is such that the sheets can be lead between the upper and lower stays getting a flatter trim and closer to the wind. Here, in 12-15kts.
Luff 41'6" Foot 18'2" Leech 32'8"