Thanks guys:
Joe,
The rear mount is VERY important on the inrunners. Otherwise the motor will wabble around.
I am using a rear mount, just trying to find a way to gage if I have too much movement or not. Rear mount is carbon screwed to formers at 4 corners, holding the mount with fuel tubing around the inside of the mount.
The developer of the soft mount is the best resource to tell you how it should behave at rest and under load. "Back in the day" when flying glow I used at least 10 different types of soft mounts over time before settling in on the Hyde mount. The Hyde mount secured the engine at two points and was both firm and allowing very limited movement. I used other soft mounts that allowed very visible movement at the lower RPMs - scary movement. But - they held and were overall secure.
Unfortunately I am the developer of the mount! Used rubber washers to isolate the mount.
I noticed that the Budd soft mount comes with "very" soft rubber isolators for the Neu motors, so I went with 'softer' rubber as well - not terribly soft, but not hard.
Budd and Hyde mounts won't really work in my plane, fuse is too small.