Rvjimd-The standard way is to let the pinion gear run against the swing gear. However I understand you have to do what you can with the room you have. On the pictures you posted,I cannot see what is what.(eyes)
Are the servos in the model mini servos? Also I cannot see the detail of the drive sprocket but that is okay. Just keep doing what you are doing and I think you will have an operating model soon.