Of course, the engine wouldn't be as stiff as with the nose ring (even if Chip Hyde is able to muont his 4 cylinders DA200 on his TOC winning bipe without nose ring... ).

I think that some real testing should be undergone.

If a nose ring should be needed anyway, the only solution is to make a new pick-up sensor case, mounted (suspended) on a different location (the two front cylider bolts?).
This mounting should be very stiff because the gap between the sensor and the magnet is critical.

It wouldn't be easy to make, but not impossible.

To put the engine in the model can be a little pain, because you have to pull the propeller attachment away (I don't remember his correct name in english..), put the engine into his place, MOUNT the pick-up on the correct position, re-install the prop attachment.