Re: gas and oil mixture
My engine is constantly run and maintained so it is very clean. I only do a decarb at the end of the season.
For engines that get little use or have sat a long time, I recommend that folks do a couple of decarbs up front, if possible letting the engine sit overnight after flooding it with the sealfoam solution. Then, after you have cleaned it out good, go to doing it at the end of the season.
John