I've been out windfoiling a bunch of times with my wife learning to wing foil. She's a lot lighter than I am (I'm 195 lb). When windsurfing, we mere evenly matched when she was on 4.0-4.2, 89 l, and I was on 5.0, 110 l. Foiling, she'd be on a i76, 4.2, 90 l while I was on i84, 5.0, 117 l.
We have only one 4.2 wing so far. (F-One). She's been using it with i84 and a 115l l JP SUP while I was on an i84, 117 l with anything from 5.0 to 6.5. I had to fight for control in gusts in a few sessions, she never had an issue. She was usually foiling as much as I was, sometimes more. She's had one session winging on the i76 in stronger winds and liked it much better than the i84 (which she likes a lot for winging, less for windfoiling).
Another big difference on the wing is that she is now usually the one on the water longer. Windfoiling, she used to come off the water before me, even though she used the harness all the time, and I use it only occasionally. With the wing, I usually stop earlier. Her longest session so far was 4 hours (without break), and her only complaint was that she started getting a blister. No harness with the wing, she does not see the point.
I'm
very impressed with the range of the wing. I can foil on my 5.6 in ~12 knots, and stay on the water in 25+ knot gusts, but it's a bit survival mode at the upper end (partly due to 3 ft voodoo chop in higher wind). Her range on the wind foil was much lower, since she did not like to be powered up on the foil. With the wing, it's no issue at all so far. The only small issue was when we had very shifty winds, where the wind would often change direction by 45 degrees and strength within less than a second. The wing sometimes would start fluttering if she was going upwind. I'd often get backwinded by the same change, or at least have some wild up and downs.
So after about 10 sessions on the wing (and 50+ windfoiling), she has about the same lower range with a one size larger foil, but a much larger upper range. We'll have to get a larger wing for me to try winging, because there's no way she'll let me use the 4.2 in the kind of wind I'd need to get going on it. It's a bit of a wait, though, since wings are in short supply in the US right now, and we want a specific one.