[Arran]

The current rating is really dependent on whatever the B+ voltage is, think of the #84 as a six pin 6X5G, basically useful for radios of a lower tube count, or car radios. Interesting that Colonial used a power transformer with a separate rectifier tube winding, does it put out 6.3 volts or 5 volts? Colonial used to manufacture radios for Sears, in fact I think they were either wholly, or majority owned by Sears. 
Regards
Arran