I've enjoyed this thread for many reasons.
Getting ready to make my first changa and i love the "you cant go wrong it just might be different" vibe i get.
I also appreciate the honesty and depth of your reports. I feel like we share similar hangups and thoughts about psychedilics in general and it's been helpful both in the "i'm not alone" sense and seeing how you manage it is inspiring.
Curious about your process for "opening the space" at your altar as i think you put it. Someome recently has been teaching me about the pachakuti mesa tradition. I generally believe in animism though i've never really called on spirits or allies the way he seems to be encouraging me to. It seems like a whole new language just to know what and when to call on. That said, it has it's own altar/psychospiritual co-worker (depending on your point of view) called the mesa that is said to be in living relationship with the practioner and has it's own opening and closing ceremonies. I'm still a bit unsure of how i want to progress with the practice and would be interested in hearing of your experience, regardless of how it aligns with what i described.
Ritually and ceremonially, I tend to be all over the place. It's often about what I feel is called for in the moment. And that's actually an embedded part of my practice. To break down and few principles so that makes sense, a simple way to describe my practice is I juggle metaphysical principles in order to hop between paradigms. It's about balance, versatility, and adaptability.
That said, I'm also a guide and one of the reasons I practice in such a way is to be able to more aptly guide more people.
Do whatever works best for you. I don't often request support from anything either. But for some, asking may be a way for them to initiate the power of that element or symbol for that themselves. It's a type of resourcing.
You may not want to call on specific animal spirits, but you can drum up and elicit attributes of those animals that you think will be helpful to you in some manner.
Opening and closing ceremony does seem to create an energetic buffer that lends itself to more clarity in experiences from beginning to end. For me, closing the space is about humility and gratitude, there are many elements and people taken for granted that allow the work to happen this moment in time, from the lineage that have passed down information that has led us to medicine and inner work, to the activists, allies, and ancestors who have played their parts as well. There's always the known and the unknown that play a part in The Work. Honor all of them.
Again, I'm all over the place. Sometimes my ceremonies are long and drawn out and other times, they're dialed in and commence quickly.
When guiding, that's different though. I'm mainly talking about my personal practice.
One love
But am very grateful right now. 
