I think that I have read every thread about 2 stroke oil and mix ratios. I believe that the bike and what you are doing with it determines what fuel/oil ratio to use. IMO the faster that you move the fuel through the engine the more oil that you need in the mix. If you are a casual trail rider then 40:1 - 50:1 should be fine. If you are a hard core racer then 32:1 - 40:1 should do. Again, I think that it really comes down to how fast you are moving the fuel/oil through the engine. I'm no mechanical engineer or anything but I have done my share of wrench pulling and this is what I believe. I also get this general feeling from all of the threads. IMO a little bit more oil isn't going to hurt anything unless you start fouling plugs. I expect that can be remedied with jetting though. I don't have any data to back this up except what feels right. I don't know that 50:1 will actually hurt anything but at 40:1 or 32:1 I don't think it will hurt anything either.
I use Maxima Super M at 40:1 in my KTM 300 on trail rides, just play riding, and racing enduro and hs. I mix everything at 40:1 and I really don't care what the bottle says. Just stay with a good quality oil. There are lots of good oils. Amsoil, BelRay, Motul, Castrol, Mobil, Spectro, Red Line, Maxima, Klotz, Torco, Silkolene, etc just to name a few. Man, there are lots of them. Although I really don't care for Yamalube I guess it is a good oil too. Just stick with one that has a good reputation and is readily available for you. I probably wouldn’t use an oil designed for my homelite weed wacker.
There are some of these that will supposedly plug the power valve. I haven’t witnessed this first hand but have read several threads about it. Also, some folks prefer synthetics, some mineral, and some semi synthetics. I really can’t comment on the advantages or disadvantages of either of these. They all seem to work well as I don’t think that I have read anything about an engine failure because of using one or the other of these.