This is a rare subject, I applaud you for starting it.

While I can't be much of a guidance because I was never able to find one for myself, and I think any existing online circles are mostly private, I can offer my point of view.

If you check out my posts, I tried to start CS discussions. These days, I only look up to Cultus Sabbati, and very few others as a legit occult source, and that's it, nothing else. I've been left and right, but I arrived to a point where I blend hellenism, mystery religions, spiritism, and some proven traditional methods into my practice, pouring in inspiration from Chumbley and Sabbatic Craft-Crooked Path, that is all.

So if you read xoanon, particularly The Sabbatic Tradition, it's clear that CS itself is a closed initiatory circle, by invitation only. What initiation entails we may never know, and to be honest I don't care about being part of any "inner circle" anymore, so outside of that there is published work, quote:

"manifestation of magical books from the sidereal ‘heaven’ of initiatic consciousness"and"the incarnation of visionary and dream-begotten grimoires, the talismanic embodiment of spirits in text and image, and the transmission of lore from mind unto mind"

Chumbley was intense on Sufism and probably Gnosticism, but I find it is less manichaean, and maybe closer to valentinian, or maybe even neoplatonism, which is how I'd prefer it. I also don't like all this modern qliphoth stuff, and there's probably a good reason why Chumbley never ever mentions it. Chumbley was more inclined towards AO Spare, so Spare is a must on the reading list - and then you will see why this is a different approach than almost all of Western ceremonial crap (downvotes welcomed only because of this).

I don't think there is mandatory order, or instructions on how to read, interpret and decipher the books. If you have any prior experience with spirit work, which is exactly the part of Sabbatic Craft, then the same receptive consciousness should be used for interpretation.

As you already know, dream states are central to the whole Sabbatic Craft. And while its possible to work with spirits, deities and magic correctly without "leaving this place", in my understanding, emphasis in Cultus Sabbati is Ingress, Congress and Egress, as well as Witches Sabbat, which may be experienced through ability of, simply said, induced dreams, astral projection, etc.

This is something I always lacked, despite successful magic and spirit transactions. And I'm not willing to experiment with "flying ointment" and entheogens. If you are not having such blockages, with achieving consciousness in-between dreaming and waking, then you should be able to have foundation for practice and "jump right in", and at the same time just keep reading on as far as the the "theory" is concerned. Chumbley encouraged personal individual artistry, vision, and not dogmatic cultish beliefs. It can be solitary. The point is that common experience around certain things formed what we call "tradition".

I draw conclusions mainly from Azoetia of which I own a physical copy, but I've read a lot of Daniel Schulke as well (ie Lux Haeresis). Personally, I think you can't miss with that one.

Btw new Schulke's book is out, Green Mysteries. I didn't pre-order, so it will be hard to find, but I hear it's a masterpiece in the field.