[Arran]

That H series speaker would go in the console versions of the 118, like a 118X, 118L, 118H, 118MX, the 118B would use a K series speaker, I have a Canadian 3118B and that's what it uses. It would be nice if you could fit an H series speaker in a 118B but I think it may be too large to fit, not only from side to side but to clear the shadowmeter assembly on top of the tuning cap.
Of course you could go the route of building a custom cabinet.
Regards
Arran