Behold, David J Windisch signalled from keyed 4-1000A filament:

600V at 4-5A would give a ballpark of 50 ohms plate resistance, low
enough for no-tune techniques.

Still haven't found that tube # tho ;o)

Parallel a few 6080's ;-)

--
Gregg t3h g33k
"Ratings are for transistors....tubes have guidelines"
http://geek.scorpiorising.ca