You need good torsional ridgidity in the fin ( spelt - use aryldite )
Sometimes full size stuff gets ' buffeting ' wich is airflow istability .
which they solve by fitting a ' bullet - fairing ' , teardrop shaped ,
at - through the intersection of the fin - stab , to guide and
smooth the air flow . It also helps the ridgidity .
If the stabs shuddering and trying to jump ship , thats 'buffeting '
Only needs an iota of incedance if adjacent to the wing airlow.
( pressure differential ) If its ' way up ' in its own clean air ,
you can feel that it flying along up there !
DRAG - tecnically a flat sheet stab is the most efficent -
In more ways than one .
IF you use a big thick blunt L.E. ' thing ' up there,
you would have a bit of drag , up high and back .
IF you had a detachable stab fitted with a couple of machine screws,
you could shim the incidance.
The other bit's a hollow fin, a guide at the base for the push rod,
and a vertical 1/4 ply 'upstand' epoxied to it,with the wire end fitted to the top ,to fit to the Elevator horn .
My profile Westland Whirlwind ( Oriental wing ), just has the push rod from the flap horn to the elevator horn,
with a guide half way along ( up ? ) And flys well enough to scare most people, but is a bit stable for combat,
so it makes a very good stunt ship .