I have used stabil and marine stabil in my boat since new in 04, and don't make the effort to find 100% gas since I use stabil or the marine version. I used the original version until I found the marine version just a year or so ago. I have not used sea foam in the boat but would not think it would hurt anything if used in reasonable quantities. Some people don't bother to read the directions, or do read 'em, and then think 2x as much is better. I do not run the gas out of my 60hp at the end of a trip or end of the season, never have, and I have not had any issues with my carbs or plugs. I use the stabil to maintain the quality (?) of the gas since a tank of gas could last me all summer long since I dont use the 60 that much. I use the TM 95% of the time, and stay within site of the boat ramp alot as well. My 60 starts everytime, with little effort and no trouble.
Putting seafoam in the engines oil is for cleaning the oil passages out of gunk, sludge, etc. If you have a 4 stroke, then add some seafoam to the oil and run the motor for a few minutes then CHANGE the oil. If you have a 2 stroker, then putting some seafoam in the gas/oil mix probably won't hurt (up to a point) but the motor will probably smoke more than normal.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.