yup. an alternative which you've alluded to would be a ball link...
that being said, where was the binding occuring? was the throttle pushrod set up per the plans?

http://www.sigmfg.com/BuildManuals/S...detLT40P4.html

if you remove the pushrod / linkage from the servo end, you should be able to manually move the throttle pushrod VERY easily.
if you can't, find out where the pushrod is binding and eliminate it.
it's probably obvious but I'll state it just to make sure: make the pushrod run is as straight as possible