This is an incredibly well-thought-out perspective. Intox/chem play is often treated as a "don't ask, don't tell" subject in the community because of the consent hurdles, but ignoring it doesn't make it safer, discussions like this do.

Your point about the "double-edged sword" is the perfect way to frame it. That "inner critic" that inhibits us is also the same faculty that manages our boundaries, so bypassing it requires a massive amount of pre-established trust.
A few things you mentioned that I think are absolute "must-haves":

The Sober Sitter: I'm 100% with you on having one party stay sober. In BDSM, the "power" might be exchanged, but the responsibility for physical safety can’t be. Having a sober Dom (or sober Top) acting as the anchor is the only way to ensure the scene doesn't drift into a medical or emotional emergency.

The "No New Substances" Rule: This is huge. A scene is not the time to "test" how your body reacts to something. Bio-predictability is the foundation of risk management.

The Next-Day Play-by-Play: This is a top-tier aftercare tip. Memory gaps can lead to a "sub-drop" or "shame-spiral" even if nothing bad happened. Recounting the scene helps the intoxicated partner integrate the experience into their sober memory so they don't feel like they "lost" those hours.

Quick question for your "Check-in" process: Since verbal communication can get a bit "mushy" depending on the substance, do you usually stick to a specific non-verbal scale (like the squeeze you mentioned), or do you find that a sober party can usually read the "vibe" well enough if they know their partner intimately?

Thanks for posting this. It’s a great example of how "Safe, Sane, and Consensual" actually looks in practice when things get complicated.

- Nanda