Welcome @jav, I've been taking 1200 mg daily (600 morning/evening) along with other neuropathy related supplements. There is another discussion on your question that might be helpful to learn from the experience of other members:
-- How much R-ALA to take?: https://connect.mayoclinic.org/discussion/how-much-r-ala-to-take/

When starting a R-ALA, some people experience nausea and stomach issues. I never experienced any stomach issues with taking R-ALA but some of those that did mentioned starting with a low daily dosage and gradually getting to the therapeutic dose in a week or so.
Here's a reference that provides more information - Alpha-Lipoic Acid - Uses, Side Effects, and More: https://www.webmd.com/vitamins/ai/ingredientmono-767/alpha-lipoic-acid. The Foundation for Peripheral Neuropathy also has some information on vitamins and supplements for nerve health - https://www.foundationforpn.org/vitamins-and-supplements-for-nerve-health/.

There is a lot of information out there and I think you are right about being difficult to find consistent information. One of the better sources I've found is the Oregon State University, Linus Pauling Institute Micronutrient Information Center which does show some dosages for different diseases - https://lpi.oregonstate.edu/mic/dietary-factors/lipoic-acid.