Oof, I am sorry about the can of worms I may have opened, regarding late implementation. Honestly, the idea hadn’t occurred to me until that moment, so I’m sorry I didn’t submit it earlier.
Past a certain point, I know it will definitely increase your writing load. I tried to consider a few vague descriptors that could cover hundreds of species (pleasing the most people, and all), but I fully understand if that’s outside the scope of your intention going forward.
Honestly, if you’re gonna have one feature that gets more attention in the writing, I figure it’s best to lean into the one you care about most, and can please a lot of people, and that you can do a lot with: the tail in this case. It’s honestly the one that appeals to me as well, so maybe I’m biased 
As far as retroactive work goes, and once you get the new contribution guide in place, please know that I am always happy to help identifying spots to place new descriptors in old scenes, along with writing lines suited for them, if that’s at all the sort of help you’d be looking for! 
I figure - seeing an optional feature mentioned in even a few selected scenes or wander encounters in each older zone would probably do the trick for the illusion of customization, and I could aim for that target.
Also, regarding the comment by @memes , you beat me to it! I had already written four separate mirror descriptions for the first four-of-eight tail stages as I gained more weight in a new playthrough, with the intent to submit them to you when I completed them all. That said, two basic ones is probably the safer and far more sane bet, instead of having to rewrite it for every single weight stage.
As for hiding text - just hit the gear icon on the post box! There’s the one called “Hide Details”, and it’s right above “blur spoiler”.
Looking forward to the new update. 