RE: vision 3d
I have flown mine with 3" stand offs and the CoG was too far forward. Re-checked the on-line manual and the latest version shows and recommends 11/4" stand-offs. (see Chips forum). In the process of re-fitting with the short stand-offs which requires F1 to be opened up and the cowl to be re-shaped. Not a problem to do but unecessary.
Adrian