8.75 Sure Grip axle end play - left side

O wise ones,

I've just installed a Sure-Grip pumpkin in my 1970 8.75 rear end. (had a non-Sure Grip before -- both are 741s) I HAVE installed the pinion thrust spacer as well. The right side axle (with the threaded adjuster) adjusts end play beautifully. The left side (no adjuster) has .070 end play. How should I correct this? I'm thinking about putting another ( .060" ) gasket between the axle and backing plate to take up that slack and put end play in the .008-.018" specification, but is the "kosher"? Or is there something I've missed?

Perplexed, I am,
JD