I did see more research after clicking around a bit...and some of it definitely makes it seem like it would be better to use only the R(+) form...but its still a tough call, many people have gotten significantly better using the ALA mix when chelating...but R+ ALA may be better for other reasons.

But there is still a lot of professional studies done on ALA, meaning the mix of both R(+) and S(-) that showed many positive benefits...

I know mercury is very attracted to ALA, which is why its used for chelating...it would be interested to know the way mercury reacts to each different form of Lipoic Acid separately.