if the tabs line up, they can be installed where ever and the board will require the exact fin tab position for any new fin. you’d be stuffed is ya broke a fin.
generic fins would sit in a different position.
might have to grind out fcsII fins to change em up, that could be fun.
… I think the board in question has the tabs already installed
to technical for me, might have to consult YODA
EDIT: I got in before ya hahaha
all remaval fins are measured from the trailing edge.
will make no difference 
I have done such things and it’s just fine. Being a plastic fin though, they get pretty flexy and soft when you reduce the base length of the tabs. Who knows, that might feel good to you!?
have you got both trailing edges lined up.
if so, thats very surprising.
… I work out of a factory that does 120-150 boards per week.
imho, I cant see the distance from the back tab to to trailing edge to change from fin to fin.
I’ll be demned if they do.
Using the trailing edge of the fin as the datum, it can still be done, but the modified fin will have much shorter tabs. Maybe too short considering it’s a plastic fin in the pic.
Lining up the tabsyou’ll have to live with the whole cluster being what looks like 3/8" or so further up. Not without consequences I’ll bet…
cough custom fins cough cough
Sorry guys… I didn’t mean to ‘start something’. In lining these up… L.E. or T.E. …the slots where the screws gain traction in the ll series are not necessarily favorable. I’ll likely save these (I’ve got a load of FCS) …and buy a new set. Custom is an interesting option - didn’t really think about it 'till you mentioned it. Thanks. Jim
