Thanks, I think that's essentially PVA glue,
whether or not that particular product is marketed that way.

Mine needs some entire sections done.. I'd be inclined to patch the front where it's not seen once mounted in a radio.

Maybe it would be nicer to wreck some paper speaker from the 80's of the same size to get patches of similar coloured paper.

I've used Helmar Acid Free glue for small tears and patches it's neutral cure, archival quality and remains flexible. You can use a tiny amount of water to thin it down a bit if you want. You need to be very careful and only do small sections at a time, the glue will make the speaker cone very soft and it's easy to do more damage. Practice on an old cone. I use a tiny artists brush to apply it. Spotlight sells it. If you're really concerned about the colour you can use a texta to colour it although I've never bothered. Another tip was to use appropriately coloured sections of newspaper although I didn't have great success with this. The finished repair was a bit stiff but I was using normal watered down PVA then. Whatever technique you use, only do small patches and rip the paper rather than cut it. The torn edge blends in better and gives a stronger repair.

While have used "Elmers" Multi-purpose spray adhesive, intended for photo mounting. I steer clear of inflexible binders & adhesives like Epoxy Resin & PVA

Normally I use an Acrylic or Butyl based type as these remain flexible. As a repair webbing I normally use non woven fabric like Medical Micropore.

Marc