--was originally formulated precisely because people with reflux and the like were reporting more symptoms with alpha lipoic (which, after all, is an acid).

The R form contains only the right-handed isomers of the lipoic acid molecule, which is the active form. Generally, I have seen ration of anywhere from 6 to 1 to 10 to 1 regarding dosage equivalencies for a given level of effect, so that would mean that someone taking 600mg/day of alpha lipoic acid daily should try somewhere in the neighborhood of 60-100mg/day of R-lipoic for a similar effect. And yes, that reduction in overall dosage does seem to help with gastric acidity symptoms.