RE: Substitute for Ether
Had a thought Andy, ever try or think of tyring to "pre-heat" the kerosene fuel. A simple coil of a couple of turns mounted inside the muffler would warm the fuel some and might aid in combustion maybe resulting in a bit lower compression; wouldn't help starting however.
Did you get you get out to the airport and inquire about the Jet-A ??
cheers, Graham