I looked at those new Fone parawing boards when they first came in. I did not like the shape and I thought the tracks are too short
I bought a KT super K2 90L (my weight 85Kg) which is proving an exceptional parawing board, it has good nose volume you can really push against in the starts and it pops right back. It's also an awesome wing board with no downside I've found. I hardly ride my 65L ML anymore.
I don't see the need for these so called parawing specific boards, some midlengths are better than others but they will all work for parawinging you just need the right volume for your weight.