RE: adjustable (turnbuckle) control rods
Thanks Harry,
I want to use M3 rather than 4-40
Maybe I will stick to steel threaded rod, as the length is infinitely variable and my LHS stocks the fittings.
As smchale says, turnbuckles are easier to adjust, but it has to start the exact size for the installation, and then you get a few turns of adjustment either way.