I have the Admiral version of that set. The set uses 300ma series tubes that are not that popular or expensive. Many of them are only $1.00 each at the Florida place. Look on the dollar list. Minimum order of ten tubes.
Naturally, the 30JZ6 is like $14.00. It looks like yours is pretty well wasted.
It looks like Wards had several suppliers at the time, including GE.