I've been using the TCW-3 oil and Seafoam in every tank for a couple of years, now. Can't say I see an increase in mileage, but I figure it can't hurt regarding fuel pump lubrication, rust preventative for the tank, and upper cylinder lube. The Seafoam I started using to keep the carbs clean. I had a idle speed fluctuation when I first got the bike. Cleared it with Seafoam, but it came back a short while later. Started using the Seafoam in every tank, 3oz. or so, and no problems since. Seems to me the bike did seem a little smoother with the oil addition, but it's been so long now, I can't tell the difference. I also use non-ethanol gas whenever possible, which is most of the time. Problems with 2-stroke mini engines turned me against ethanol gas a long time ago.
These are the times that try men's souls. The summer soldier and the sunshine patriot will, in this crisis, shrink from the service of their country; but he that stands by it now, deserves the love and thanks of man and woman. Tyranny, like hell, is not easily conquered; yet we have this consolation with us, that the harder the conflict, the more glorious the triumph.
Thomas Paine December, 1776