What type of oil finish? Oil based poly? , Actual oil?, etc.
If poly ... use the hard pad and Cristal 80, 60, or 40 depending on what does the job best. If choosing one grit go with 60. Otherwise start with 80 and if that doesn't do it work your way down. I don't remember if you got the /3 or /5. If /3 then the 40 might not do as well.
Seth