It was done in 12k Carbon,instead of the usual 3k-a big mistake,flex wise.Also,did a fair bit of extra work with the fin box,as I’d left foam in the spine,as well as the usual extra layers building up the spine.I added a further 7 from memory.As mentioned,because of the foam in the slot area,I cut out the foam to the bottom of the board,about an inch(25-30mm) all round & glassed in a SOLID block of fibreglass with carbon rovings,then slotted the block to match the slot already in the bottom of the board,then glassed the deck as usual,& added the spine & rail reinforcements( only 3 staggered this time,as I considered it stiff enough-normally you add 4 staggered pieces of “scrap” carbon to the rails,& sand/tune the rails/tail area).