After having done a few more of these setups --I found some other methods which work well -if servo location and engine position cause questions.
First - cut off the choke arm end piece-
use the supplied arm ball link
make a bellcrank from a round servo wheel and position the choke arm so that it pulls easily and snaps to "off" easily.
On two models , I made the choke exit at aft end of cowl-on top!
The assistant places his finger on this rod and when the engine burps , he pushes the arm "in".
Done right - the engine catches and runs.
Don't put yourself at risk doing this!
(do as I say -don't do as I do)
The throttle arm , I attach to the existing end plate with a 4/40 bolt and nut and a copper tye wire to stabilize it.
Also - look at the geometry of the servo pushrod -
solidly position the throttle arm to provide a nice 50/50 throw , about center of throw.
Also set the radio to deliver 100% (aprox) of stick throw when the throttle moves 100%.
This may sound strange--but it permits the idle throw (trim) to adjust nicely from a high to a shutoff position.
The c/l of the throttle shaft to the c/l of the attaching ball link, is better if this measurement is aprox 3/4"-1".
The servo output arm will then have a output of aprox same length.
Result is a full , 100% throw
This setup, minimizes slop and bend losses.
Also remove the throttle stop.
Finally, setup the servo such that the servo PULLS to OFF.
Set max throw for open , just shy of a solid open position-to avoid jamming the servo when flying .