While on the subject. I've got that exact board and would like to add a mast box. Could anyone give directions on suitable distance from tail to center.?

I have a big red with the mast track installed that came from Wardog's 2nd batch.

The mast track box opening is 6 3/4" long with the back 1" routed out for the bolt entry. The front of the Box slot is 78" from the back of the tail.

It would be better if the box was back a bit more.  Although I usaly like to use double bolts, I can not get them far enough back and have to use a single bolt 5" from the front of the box / the back most posible position.

That position is ok, but A little futher back would be better for old school WS One Design type free style tricks and wave sailing.

So I think 3" further back from the stock position would be better.

Note that I typicaly like to be slightly under powered on the way out for better surfing ability on the way back in with the added wave apparent wind . . .