I put in 120 ml of Peaty's sealant with (biodegradable, non-microplastic) glitter, and although it is probably too soon to declare victory, it looks like this is working. (I added it to the Orange Seal; they are compatible, and spun the tire around before and after inflation).

I had a 120 ml trial pouch. It fit my Peaty's valves, so I figured I would get one and see how it behaved. If this holds, I am going to switch to it.

https://peatys.com/products/holeshot...beless-sealant