Continuous rotation servo controls are for continuous rotation servos. 

I believe you’re asking about ezrobot grippers? It’s probably best to use the Auto Position control. Here: https://synthiam.com/Software/Manual/Auto-Positioner-Gait-16057

Optionally you can use a horizontal or vertical servo control for manual use. Here: 
https://synthiam.com/Software/Manual/Horizontal-Servo-16098

Thanks  for the response -  I will try all your suggestions,

Angelo,

by the way I did post a video, as you suggested, on my modified Adventure Bot -