Most 2/'s will produce max power at a ratio around 18/20:1, contrary to the "conventional wisdom" that less oil produces more power. As for spooge, until you get below 16:1 the spooge is a result of improper (too rich) jetting. Even when we ran a 16:1 mix, we had no problems with spooge. However it was not unusual to change jets 2-3x's a day. Your typical recreational rider rarely ever changes the jets and consequently can be too lean at times but more often than not too rich.
I think it is Maxima that had some decent web pages that showed oil deposition and gave some good recommendations as to premix ratios needed to provide adequate lubrication.
With straight synthetic, the top end looked great, no problems with gumming up and sticking a ring. However on engine teardown, there was minimal residual oil coating on bearing surfaces, etc. With straight castor, it would have a tendency to gum up the rings and leave more residues on the crown. However in engine teardown, the lower end looked much better and had more residual oil film present. That's why we blended a full synthetic with a castor. Trial and error showed a ratio of 3:1 worked best using the oils we did in our engines.
BTW, if you read that Gordon Jennings paper on 2/'s, you will have a better understanding of a 2/ motor than 90% of the people that ride them.