I always used ATF ( Automatic Transmission Fluid ) in my Scottoiler on my Triumph. Stood to reason because ATF is specifically designed to keep rubber
pliable and in good condition inside the transmission.
It did a nice job of keeping the chain very clean.
It is light weight so it also kept the back wheel nice and filty.....
very Macho ....
I do not have a Scottoiler on my current Trumpet ... but I do wipe the chain down with ATF ( and still use some spray on stuff )
Another oiler system may be in cards.