Hi Spiff,
The problem with foam-surround repair is that the compliance of the repaired surround may be quite different from the original foam, so the performance of the driver may also be quite different from spec.
I don't know anyone at Snell anymore, but they may still have stock or replacement drivers that meet the original spec. Given the vintage of your Snells, I'm fairly certain that Kevin Voecks designed them (he now heads up Revel), so he might be a help. I'll see if I can dig up Kevin's email address and I'll send you a PM with it. He's an old friend, so you could use my name.
Regards,
