I'm 175lbs and have 8 and 10 SLS Neos. I've been riding Neos since 2017 models onwards. I mainly ride strapless freestyle and then waves when we get them, but not very often.
Neos are gruntier than Reos, so I don't know if you have been able to ride Reo 9m at 15knots? If so, then for sure Neo SLS 9m will work well. 10m is quick but it's still in between the bigger and smaller feeling kites, ie 9m and 12m. However, 10m turns well, in good winds I can loop the kite one handed very well when doing rodeo. It drifts a bit better than the normal version, and I find the highend to be better as well.
For pure wave riding at 25 knots avg. wind I would def. choose smaller size, I'm very happy with 8m then so perhaps 9m would work for you. However, at 15 knots without bigger gusts, I would say 9m might be a bit struggling?
Hope this helps a bit.
Have you checked this review for example (many can be found online)?:
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