Less oil, is a leaner mix.
More oil, is a richer mix.
I've never heard of someone melting this pistons from running too rich. Lets not start this again, potato/pa-ta-toe... thanks.
Throw some race fuel in your 93 mix, depending on your elevation, this may be a nessessity. If you're really worried about it leaning out then bump your main up a size or two.