Excellent questions. Unfortunately, as I noted in my recent post "On Thelemic 'Attainment'": If you explain the method involved too plainly -- and too soon -- thereby alerting the conscious mind to it, the process ceases to work so effectively as it otherwise will...so, as usual, I'll keep this somewhat indirect and hintful in a public forum.
1. The resolution of apparent contradictions in his work -- particularly on issues like this one -- is at the heart of unpuzzling what AC is on about. Those who simply shrug and assume AC was confused (the opposite of what you're doing here, and good for you) will tend to miss his underlying points. Hint: as most of us (and certainly you) do, sometimes he's making hardnosed assertions of fact; other times, engaging in reassuring poetry. I've repeatedly, including in that post, noted several of his works that lean more to the former than latter.
2. One's "inherent True Will" is one's essential nature, the set of drives, potentials, etc., that one arrived with. Its expression will vary wildly over time: with changes in environment, development of skills, and so forth. It's more like the natal chart -- a set of potentials which may be used in many ways -- than (as it is so often misread) "The One and Only and Permanent Right Job For You." Those who discover this fact and think they have advanced beyond AC's insights need to read AC more carefully.
3. One's "inherent True Will," then, is "omniscient" in that it comprehends (i.e. includes) all of one's nature; it is "omnipotent" in that one ignores it at one's peril. Its internal "omniscience" (in the sense named) does not extend, particularly at first, to a perfect understanding of external circumstances; its internal "omnipotence" (ditto) does not extend, particularly at first, to a perfect, or even a passable, control over external circumstances. As I also said in that post, initiation involves examination of one's self-contradictory nature and goals -- conscious and unconscious -- and reconciliation of same into a unified whole. As Crowley's "One Star in Sight" puts it, the aim is to free one's "Understanding" from "internal contradiction [and] external obscurity."
4. Finally, the notion of a "True Will" is provable without recourse to superstition, or reliance on authority, of any kind. Put it this way (as AC himself does, in Diary of a Drug Fiend, IIRC, among other places): any object -- you & me included -- has some set of inherent qualities, hence a range of "best uses" in given circumstances. That circumstances can and will change, and that one must reconcile contradictions in one's nature (and goals) to make the best use of those inherent qualities at any given time, does not invalidate the concept of a "True Will"...it simply justifies the utility of initiation itself.
Terrific thread, sir. Hope this is useful.
93 93/93 -- AJ