In all my years of running 2 strokes: saws, boats, snowmobiles, lawnmowers, hedgers, power prunners, ect., I have never had an oil related engine failure.
I know a guy that had a crank seal go out on an 066, not sure if that's oil related, but that's the closest I can think of, and he was running stihl oil.
The wife even ran a 1 gallon tank of straight gas through the lawnboy once about 8 years back and it still runs fine.
I read in a manual(forget which one) that in a pinch, just use 30 weight.
I figure if it make you feel all warm and fuzzy to run a specific oil for each tool, then do it. Otherwise just have some oil, of some brand, at some ratio, and have at 'er.
You will NOT have an engine failure because of the brand of oil you use. You will also NOT have a failure if your ratio is off by 10 or 20%.