I used a Dubro vibration mount on mine ( pictured above ). It is all the mount you need and the only one I use on on my glow engines. The one I used on the Venus II is a #686 which has a bit smaller footprint than the 688. I turned the tank sideways and dremeled a bit of the former out so I could lower it and mount the engine fully inverted - mine is a non - pumped engine. Looks and works great that way. Treat yourself and use an inside header and a flex pipe so the muffler exists under the plane as in the above pic. I get very little residue on my plane that way.

The 120 FS will give you unlimited vertical and only uses 10 - 12 ozs. of fuel per 10 min. flight.