Try Black project -I just bought some 13cm minituttles for my 99 thruster and they're really good - work better than the stock fin 10cm with the 23cm x wave smooth, quick and fang upwind - feel just as good on a wave - i was surprised how well they worked as I thought they may be a little big.

www.blackprojectfins.com

Product ID SIZE BOX PRICE AREA
11WMU10 10 US/Slot /MT
11WMU11 11 US/Slot /MT
11WMU12 12 US/Slot /MT
13 US/Slot /MT
11WMU14 14 US/Slot /MT
11WTPU15 15 US/Slot /MT
11WTPU16 16 US/Slot /MT
11WTPU17 17 US/Slot /MT

Not sure who stocks them here but pretty good price on line as well

Hey save the whales - Tried mine out again on the 99 thruster 2 x 13cm and 1 x 23cm stock x wave with 5.6 S1 severne- I reckon you could get a way with a 20 or 21 cm x wave fin with them - work really well nice drive off a bottom turn - still get a bit of slide off the top and - sounds strange feels less finned than when I tried a MFC 24cm FPT and stock 10cm bites.
. Really happy great finish and work a treat. Main comment from crew was - wow that looks way overfinned!!!

By the way I,m pretty happy with them