They are both good boats. I have owned both.

Regarding the F17 jib-kit you mention: I have only seen the jib kit on an F17 once. I have only heard of the boat being seriously raced single-handed & unirig.

Regarding double-handed sailing: When it was blowing 15 mph I would double-hand the F17 with a friend. We were a little shy of 350 lbs. The boat went fine (caveat: we were doing this on an inland lake, not in big swells). The boat only had one trap, so only one of use could hang out. But if you are primarily interested in double-handed sailing, the F16 might be a better choice. Don't flame me, I said, "might."

Also, I have heard that the carbon mast is now an upgrade on the F17. Carbon used to be standard. Make sure you consider this when considering new versus used F17s and comparing prices.