I run about 1qt to a fill up. 2 stroke, non detergent 30wt, or what I drained out at the last oil change.
I'm thinking it adds a little lubricity, but you wont see much effect on performance. If you go with a bigger dose, depending on where your timing is set, you might actually notice it running a bit quieter, & see a little change in milage, as it slows the burn rate a little.
(& I THINK it adds a little BTU content.)
Billy, hit that Mopar man link, is an intresting read, I checked it out a few months ago.