<I've been thinking that I'd like to use a clear rubbery type of glue that I've found on some speakers, rather than the white glue type that dries hard like Aleen's Tacky Glue which I and many others use.>
Actually, Aleen's Tacky Glue is clear when dry.
I know, I've used it on a couple dozen woofers. It's not rubbery at all though, it dries like white glue although perhaps slightly more flexible than Elmers. Can you imagine trying to remove that? I'm looking for rubber cement that can be peeled off in 20 years.