Would you consider the thoughtform an access point to a higher reality, or would you say it has power in and of itself?
Mmmm. The former, really, but the latter will probably develop as some sort of personality.
Probably be best if I give an example -- one concept/energy I've worked for a while with is roughly vitality, a lust for life, the life-affirming power of desire, and I usually label the abstract essence something like Desire or Lust or Life (let's call it DLL for short). In a sense I believe this abstract essence exists independently, and I also believe there are 'echoes' in my subconscious.
That's where the thoughtform comes in. I think of a being that, to me, embodies DLL, but equally importantly reflects me and how that DLL manifests in me. Since I'm into words, visualization is less important to me than naming the thoughtform.
And this is the part relating to your question: I treat the thoughtform as a conduit between DLL the abstract essence and DLL in everyday life. Just like you have those things in between the electric generator and home power socket to amplify or (erm, what's the opposite of amplify?) voltage and all that.
That I personally feel is the simple bit. But I'm pretty sure that anything personified will eventually get, you know, a personality, though unless I write some 'myths' the personality probably won't be anything more than what you'd ascribe to a cranky computer. And at the same time I can't shake the feeling that DLL the abstraction, the thoughtform, and DLL in me, are all the same thing.
Or the feeling that this is all very elaborate gibberish to enhance role-playing.

P.S. I used to refer to DLL as Eros, and I think at that time the relationship was more like a typical supplicant-deity one because Eros had his own Greek and Freudian associations which included nothing of mine. Eros provided access to DLL, yes, but there was a distinct sense of separate selves, whereas including myself in the process makes everything feel...tighter. 'Conjoined'...
P.P.S. Comparatively speaking, what I'm doing probably falls under or at least mimics invocation.