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There's a guy over at the Runryder forum that flies the vario you mention. His handle is Dr.Tim. He could help you on that one.

Vario Benzin Machines
 

I like the four servo setup, it seems to be more precise and is in actually easier to set-up. Down-side is you need another quality servo...

CCPM is by all standards the current hot set-up IMHO...

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3 servo CCPM is easier to set up, and has virtually no chance of the swashplate binding in extreme manouvers. 4 servo CCPM requires more persise set up and works well for scale flying but has a chance of binding up under extreme 3d manouvers.

For pod and boom and sport scale fuselages the 90* 3 servo set up is all we fly. For scale fuselages that cost more money and have hours of building time invested in them the 4 servo set up is highly recomended.

3 or 4?
 

I agree with Moore-Vario. Think of a 3 legged VS a 4 legged stool. A 3 leg stool will always have all legs touching the ground no matter what. On a 4 leg stool, every leg better be exatly the same. No margin for error. Binding is real possibility with a 90* 4 sevo set-up. I read where James Wang started with a 4 sevo set-up in his X-treme but soon switched to a 3 srvo set-up. I use the 120* 3 servo set up in mine too. At least with Vario, you can switch between 120* and 90* set-ups and try them both.