The jug is now empty, all the TriLyte (ten and a half glasses) has been consumed, and I'm definitely a lot cleaner inside (and still getting cleaner) than I was. The liquid did get pretty unpleasant to drink, but after the break I had no more trouble with nausea. I found that rinsing with plain water or white grape juice (which I'm allowed) helped clean out the flavor between doses--I could have drunk the grape juice, but I was drinking more than enough already.
Vaseline is proving helpful at keeping my anus from feeling raw.
I had only the bits of nausea, never had any cramping or other side-effects. A bit of mild "feeling chilly", but that's partially not having eaten quite as much and the effects of constantly consuming cold beverages, and nothing that a blanket doesn't handle perfectly well.
And that is, by all accounts, as bad as this entire process is going to get. Hooray!
I can continue with clear liquids (clear broth, yellow jello, soda, tea, coffee, water, fizzy water, etc.) through 3am as I wish.