i have not done it with a lister, but i have with a 12 hp changfa and propane
the engine will run on propane and will consume less diesel, how much i dont know because i havent ran through all the testing,,, yet,
but i certainly plan to.
there is no reason that a precup engine, (indirect injection) cannot be used in dual fuel mode, but maybe not to 90% , pilot fuel (diesel) amount will be higher, likely over 20%.
u will probably have to advance the timing to optimize power, but you should not have to decrease the compression ratio.
natural gas, propane and methane all have sufficiently hi octane rating to negate the need for lower compression.
flame propagation will for some of these fuels be slower so the timing may need to be advanced.
again this is to optimize power output, and may not be necessary for all folks, all engines, or all applications
bob g