Also, the new boards are Tuttle Box and many of the 59cm boards were Power Box.
I purchased some used Rista fins for my 183x59 Cabrinha board. Quad fin set 33.5cm rear and 37.5cm front. The set was originally for a 65cm RRD board, but I figured I'd give it a try. The fins are oversized. OK to ride in light winds though. Goes upwind like crazy compared to the old fins, but I get overpowered very quickly and need a ton of foot pressure to keep the board flat.
Still on the lookout for a used tri-fin 70cm board. I'm hoping all those olympic windsurfers will want to dump their 6 month old gear they bought during kiteboarding's brief time as an Olympic sport