Looking for user reviews on this size around 90kg

Fanatic 8,8 just plain unstable

Starboard pro 8,5 even more unstable

From what I read the jp surf 8,6 are the most stable of these for such performance boards

Can't say re: the JP, but I find that a wider tail or more parallel rail helps a lot with stability...

- wider tail ie. Sunova Flow.
- parallel rail ie. Infinity B'Line

pretty simple and obvious.. once you go below 30 inches you are definately going to lose stability..
but if you stick with a board with wide point further to the nose, and keep the forward 1/3 of the board still quite round and full its really going to help.. take a look at the smik hipster..

here ,,, i found a great review for you from SUP International.. on the Smik 8,0 x 30.5.. dont get too hung up on going narrower,, its a hoax.. why do you think so many guys end up selling mint pro boards after a few months? they cant ride them in anything but low wind no chop/backwash conditons.. duh not the real world unless you are cruising the island reefs..

Performance
The 8'0 Hipster didn't really feel that small in the water at all, in fact it felt comfortably stable for my 85 kg frame,(I normally ride a 100L size board). Its wide, soft railed nose pops over the white water and feels very amiable in choppy conditions. Paddling into a chunky, choppy Atlantic wave on a wide twin fin I thought would be a bit of a challenge, but the Hipster seemed to slide into the waves easily and has a ton of grip for a full compressed bottom turn. The surprising ace up its sleeve was the immediate controlled change of direction you could drive out of this board. The Twin just grips and spins around in such a tight radius it surprised us. It rebounded easily over white water sections which you quickly catch up to - be prepared to go faster than you maybe have on a sup before. So yes, we really enjoyed this board. It's more stable than the dimensions suggest, slippery across the wave and turns beautifully and doesn't get hung up in the mush after your final manoeuvre. This 8'0 feels more stable than many bigger 'Pro' style boards but proved to be tons of fun in a range of conditions. A cracking board and great value for a carbon build too.

im currently on the Starboard Airborn 8'8" x 31.5. im 6'1" 85kg.. this board rips.. looking to step down to Smik 8.0 or even 7'10" looks doable..

this is what im ridng.. www.seabreeze.com.au/Classifieds/Stand-Up-Paddle-Surfing-and-Cruising-Boards/~-7cm4/2015-Starboard-Airborne-88-X-315-X-37-123-Litres-8-8-315-inches.aspx?
this one for sale in WA now.. buy it! my buddy is 95kg nugget and he rips on the 2017 model.. same board except 2017 is 32inch and the later graphics..
Starboard dont make these after 2017.. why? obviously not enough volume sales.. usual story.