azuli said..
I restored a Mistral Superlight about 3 years ago. They are a great board worth restoring.
I felt that the original rotating plexiglass fin was a weak point so I removed the black plastic box insert, and formed a power box fin adapter in the recess using fibreglass / resin. I did not have to route / cut into the hull as there was enough space to house a power box base in the formed structure. this allowed me to use larger fins with my demon raceboard sails without fear of snapping the fin under load.
The board is amazing to sail in light - medium winds and much faster around a race course than an LT.
I sold the board to make room for some other resto board projects but still have some parts, PM if you are in Oz and need something.
Will no doubt do something similar with mine,. Thanks for the offer, I'm in the UK, but hopefully visiting my daughter in Noosa in August, assuming Doha is allowing flights! Should have it on the water well before then for the UK summer. Cheers