This still looks like the best approach IMHO even
if I thought of it :)

The throttle cable can be direct connect with
a 10-32 collar for zero back lash. No levers,
no ball joints, no clevises, no pivots.
Just three inches of travel for quick rough
settings and vernier for fine adjustment.

I found some thin wall SS tubing from McMaster
Carr to make it out of.

Anymore ideas, flames or constructive criticisms out there?

If not I'll work on refining the design.