Re: would you mix 2-stroke oil brands???
About 14 years ago, when a gallon of gasoline was less expensive than 2-stroke oil, I thought that if the label on the container said TC-Whatever, the oil was ok. Not so, at least in my experience. I grabbed a couple of gallons of Wal-Mart 2-stroke oil thinking I could save some $$$. I could not believe how crappy the engine ran. Noteable power loss, smoking and there seemed to be a lot of soot on the prop. I could see a "sheen" on the water around the motor at the marina. I drained the injection tank and have used one brand of oil since. I'm sure that today there are lots of oil that are compatable and could be mixed or substituted. Personaly I would wait until the tank is low before switching. Also, it would enable you to see the results right away. I'm sure when you read where I used Wal-Mart oil, you said, "There you go..." Try this on for size... and correct me if I got the details wrong. An Alaskan MD-80 went down off the coast of California because a jack-screw failed in the tail section. The reason it failed was because it had little or no lubrication as a result of mixing two non-compatable lubricants that if used alone, either one would be ok. At least you are already on the water if something does happen.