I know 50:1 is manufacturers spec for Stihl and Husky, and I've been told and seen on other posts that up to 32:1 is better for long life. Is there any power loss as the oil ratio goes up, or just more smoke? At what point does the spark plug get fouled up? I've been running 40:1 because I have a 4L can and have 100mL bottles of oil...