Thanks for the replies, guys. Today I bought a gal of Byron's 5% but with only 16% oil mix. How many oz of castor oil do I need to add to bring it up to 20%? MY Magnum .52XLS instructions say use a 10X6 for breakin, same for the Irvine? I have a 11X5 on it now. Too many people here now to try it out. Maybe tomorrow.