FWIW. I still use a TVO/Petrol engined Ferguson TE20 tractor. It has a two compartment fuel tank - one for each liquid & selected to feed the carb. via a two way tap.
I don't bother with the TVO equivalent nowadays (there is a formula) as it never vaporised well enough and the scraper rings took a little into the sump so apparently it 'made' oil. In fact it was of course the paraffin going down & diluting the oil which wasn't a 'good thing'.
Cheaper to save the bearings and for the relativley low hours per year petrol is always in both tanks.
Used it today in fact, with PTO driving a 6 ft topper, to cut the airstrip here in sunny Sussex.
mike hallam.