I would be a big spender and purchase a quart of 10w30 Mobil or Pennzoil and know I am using the recommended viscosity. Ed
Its not the ash tray money guys.. It the fact I have oil bottles all over the place.Definitely some logic to this answer only I would suggest a gallon of T5, it will last 7 years if doing annual changes. Wally has it for around $18 which works out to about $2.50 a year.