I used to be a Golden Spectro guy back in the 80's. Decent oil, decent protection, and the Spectro was cheap.
Now that I don't have to be so cost anal, I've been running Klotz R50 @ 42:1 for about the past 12 years. I am very impressed with this lube. The most impressive aspect is how clean my power valved engines look after a teardown. The key to telling superior oils from basic oils IMO is on piston wear at the exhaust and/or intake bridge. This is where pistons usually take a beating... with Klotz all's I ever see is a slight wear line.
I also run Klotz R50 (24:1) in my CR125 shifter kart (which see's sustained rpm's of 12,400 rpm's for 10 min. almost straight out. I did a top end inspection this winter, and everything looks great. I'm a Klotz guy to the death !