Do you really need to use bar & chain oil in a chainsaw, or will a straight 30 weight, 5W-30, or 5W-20 work? I borrowed a neighbor's saw and the reservoir is dry. I don't want to waste time making a trip to the store if something I have on the shelf is just as suitable. I have some PYB SAE HD-30, SynPower 5W-20, and G-OIL 5W-30.