The kerosene has more energy in it than Heptane does, so modern Diesels really do need or should have kerosene as that’s the fuel that’s actually burning and they would perform poorly without it. Drone Diesels used heavy mineral oil and ether only due to the fact the fuel has such a low energy density. If you run a vintage drone Diesel on modern fuel, you’d probably blow it apart due to the high energy contained in the fuel.

Don’t forget that model Diesel engines are not Diesels in the truest sense, but more of a controlled detonation engine. Ether detonates extremely easily and is the reason model Diesels actually run. Slowing the detonation rate of the ether would simply make the engine have to work harder (read higher compression settings) and likely be harder to tune/set. Correct me if I’m wrong.