Use modern oil, but before your done and put it into storage mix up some Coleman fuel with double the amount of 2 stroke oil ( I assume your engine calls for 16:1 so do 8 )
Drain the fuel out of engine and run tha carb dry.
Flush the fuel system with the mix coleman fuel, remove the plug and pour some into the combustion chamber. Do the same from the carb side too.
Flush all that gasoline and ethonal out and no worries about rust in the future. Between the oil and rust inhibitors Coleman already uses you will be fine.
This sugestion BTW is my own trick used many engines over the years with no issues but I am not the only one who has stumbled upon this.....
I have reservations about running an engine on it however unless its a true antique like these designed for white gas.
The important thing is Camping fuel is extremely highly refined. It will not damage engines and fuel systems, ever......
Maytag Gas Engine junk yard special #12 - YouTube