Welcome to the forum. sometimes we are a bit slow on this forum, but we do have a bit of experience with the Canadian radios like Rogers,
DeForest Crosley, Sparton and Majestic.
I have quire a few of these in my collection and I get every Rogers tube I can find.
I do have a 6B7M tube that tests good, and as far as I know, there is no sub for it.
If you send me a personal message or email me we can get some sort of a plan in action to get you the tube.
I also have the schematics and alignment information for this radio if you need it.
It looks like you are going to need a couple of knobs also
[ Just a note here for you] When you are asking about a particular radio the serial number does not mean much.
What we need is the make and the model, and in the case of Rogers, sometimes the only thing you can get from the rear plate is the Type
PS I find it hard to send a personal message on this forum, so if you can’t do it let one of the administrators know
Dan Walker in Calgary