problem one will be balancing forces if combustion is taking place on one side. also i don't see why this should be burning less oil. you are smearing the oil constantly around.
Here's what their webpage says:
> The seals do not experience centrifugal forces, and can be lubricated directly by metering small amounts of oil directly to the sealing surface through the housings, which means that oil consumption can be reduced to levels potentially comparable to that of a 4-stroke piston engine (essentially negligible).
Obviously take all this with a grain of salt. I haven't read any practical studies on this.