I know Metametrix has a GI panel, but I haven't been too impressed with other lab work I've gotten through them and tend to be biased toward Diagnos-Techs. They are perhaps the most experienced lab in the country and have outstanding quality control. I've been happy with them.
Haven't heard of "nebulized" glutathione. Can't comment. Can you send me a link? I use a transdermal form, though it is not readily available unless you can get it from your healthcare provider (under the name: Oxi-Cell or the more concentrated Super Oxi-Cell by Apex). The product is pure genius. Also very anti-inflammatory.
I've used a variety of nutrients and antioxidants to support eliminative organs and processes. I actually did a bit of a detox (Mastercleanse--sans cayenne--and then Biotics's) beforehand, plus quite a daily cocktail of nutrients too numerous to mention, but partially including whole food-based vitamin C, B-complex, CoQ10, Selenium, vitamin E (glycerine based and gamma tocopherol-rich), R-Lipoic Acid, N-acetyl cysteine, bile thinning and emulsifying agents, glandulars and tissue support, EPA/DHA, magnesium (glycinate, aspartate and gluconate), cod liver oil, extra vitamin D3, and numerous methyl donors. Green drinks, too (NanoGreens).
Stage one liver detoxification is driven by an enzyme called "Cytochrome P450", which is a largely magnesium dependent enzyme (also needs zinc, copper and vitamin C). Don't skimp on the magnesium. Stage two detoxification relies on numerous pathways: glutathione conjugation (brassica family veggies are helpful, E and selenium, zinc and copper), methylation (B6, B12, folic acid, DMG, TMG SAMe, betaine, methionine, phosphatidyl choline), glucoronidation (EPA/DHA, D-limonene--found in the skin of lemons and limes--perhaps an argument for using lime/lemon juice as an activator), sulfation (sulfur-containing amino acids: cysteine, methionine, taurine), sulfoxidation (molybdenum--commonly deficient in the Pacific NW), acetylation (B-complex and C), and amino acid conjugation (amino acid glycine and protein-based foods).
Drink lots of water (1/2 your body weight in ounces per day) to assist in keeping your kidneys going. CoQ10 is a help to pretty much every major organ, including this one.
For maintaining electrolytes and trace minerals, in general, I usually recommend Trace Mineral Drops by Trace Minerals Research (widely available) as a superior ionic form--though one could probably get by with Alcer's unsweetened "Electro-Mix" (from the same folks who brought you "Emergen-C".
I keep FlorEssence on hand "just in case", but things have generally gone so smoothly I haven't really needed the extra detox support. It's a nice one, though.
Don't be too fearful about diving in. "The water's fine!" Just go slowly and listen to what Jim Humble recommends. I'm not into the idea of getting too adventurous with this stuff. It's too new a frontier for me and I'd rather not be a sacraficial lamb to the cause of mapping new territory, if you catch my drift.
Given how conscientous you seem to be I think you'll be pleasantly surprised at how smoothly it all goes. No worries, my friend.