i just noticed today putting on the fin inside the tuttle just in line with the surface was a bit loose and wobbly and had to tighten more to make a rigid fin however the fin left about 2mm in cavity does this affect anything if it does what
and how do i shim it to tighten it just flat along the surface
dont worry about it you will find every tuttle fin base is different , there is about a 20mm clearence from the box to the fin base,
what he means is the fin does not bottom out in the cavity. The tapered sides is what makes it tight (it is a wedge shape). So your fin or your box has worn and to make it tight the fin has to go in deeper.
You can put waterproof duct tape, electrical tape or similar on the sides to make it tighter. Keep adding tape until it is flush with the bottom of the board when the bolts are done up tight
cut squares of coke can are better shims than tape with associated sticky glue issues.
Yeah but may be sharp on your fingies!! 
and glue can be removed 
OK better: the clear plastic used in shirt boxes (do they even box them anymore?) .... same stuff that is used for a clear window in boxed goods like kids toys. I collect that stuff for shimming US box fins too
who the f$3k buys and collects shirts in clear boxes and kids toys these days?!?!
just jokin'
