WOBBLE is NOT acceptable on a flying aircraft of any description. In your case you should "cage" the vertical and horizontal stabs, all around.
By this I mean attach wires or strong threads to both sides of the vertical and to both sides of the horizontal stab and link them together.
For reference look at the tail of a Piper Cub or similar.
If you don't I have a slight "feeling" that the CLAMATO won't be around too long.
Even downunder.