Relation b/w futures and shapers fin markings "pictures fixed"

Im trying to work backwards to get an estimatioin of fin placement based on a screen shot of the futures fins on the bottom of the “firewire cornice”.

The gearbox quad set up PDF has the shapers marks i mean, and the picture of the tail is what im working bacwards from, (its now got ruler marks all and notes all over it.)

with fcs 2 and gearbox fins the line between the two shapers marks is on the inside edge of the fins. But as you would know the fins sit inside the shapers marking.

I have done some marking and measuring on a print out, then some ratio calculatiuons to get estimates.

Eg the wide point is 17 13/16=452.4mm on the picture on my paper its 107mm


107 : 452.4

   1  :  4.22

then multply an measurments off the pic by 4.228

Blah blah blah my head hurts…

But i have based them on the back edge of the fin slot. I can and and will work backwards from these and layout mine accordingly but just thought any futures officianado’s may have a better idea.

I guess the actual question is, "What wouuld be the measurement from the bottom shapers mark to where the back edge of the fin slot would be?)

I think my pictures failed