Was thinking about making attachable felt outer soles for river crossing/playing camp shoes (generic crocs) then decided will put little silicon treads instead.
But think Buytl rubber might adhere a lot better and probably grippier too.

Any other mastic sealant you might consider better for the task?

Then also considering carrying a small tube and apply it to the hikers the night before a slick water section or steep granite section, for any shoes I might have that I know will not perform ideally.

Any thoughts?