The MMS2 baths and enemas are still experimental and have not been approved by Jim Humble yet. But I have done both and benefited from them I feel.
For an MMS2 bath I would start with 1 tablespoon (15 ml, .5 oz.) of MMS2 put into the water while filling the tub. It needs to be activated by the water so that it turns into hypochlorous acid. I was using 2 tablespoons when I was doing MMS2 baths and not having any problems so you can probably work up to that. One person reported using a roughly less than half a cup of MMS2 in a bath and it caused him to have some skin irritation and itching. Here are some good MMS bath testimonials genesis2forum.org/index.php?option=com_kunena&func=view&catid=8&id=1951&Itemid=66#3368.