I think the big fin needs all the base. Two fcs size tabs won't be strong enough.
The rear centre one should be okay.
I broke off one of my small side ones at the base, but I'm pretty sure it was a legrope problem, it was tangling my feet too..........any excuse for bad surfing.....
....well, i guess i'd better order a 'probox' back box , in that case ....
[or else try to make it into a FIN BOX base ...]
hey , i tried out the small one-tabbers in waist-high little peelers yesterday ...[they were trailers for beerfan's cutaway twin keels ] they felt good , no spinouts ...might use them as front sideys a la herb's 'superchargers' , next time ! [with small, 'M3' sized template back fins , probably ]
by the way ...it's only 5 days till simon arrives here now [all going according to plans, that is ?!]