You are getting 6.4V across the filament - which makes sense at 124V at the wallplate.

I expect that your transformer is good.
I expect that the elevated B+ is due, in part, to excess capacitance. 6 - 8 uf may not seem like much from 30,000 feet, but it is a 33% increase at ground level. And 6 - 10 uF is a 67% increase at ground level. And, of course, an 11+% increase in wallplate voltage will contribute significantly.

Do you have any replacement tubes in your inventory?

If not, contact me off-group. I probably have dozens in that line-up and I could send you some proven-good for testing. Also, can you do an alignment?

Peter Wieck
Melrose Park, PA