tube coils

Has anyone had experience using an 838 triode? These bottles can handle 100W
of plate dissipation off of a big graphite plate. They run at 1250V -at- 175mA.
The base is the jumbo 4-pin with a bayonet-stud shell.  A pair of these should
a nice blowtorch. Anyone ever make a TC using these tubes?
Thank you.
Ralph Zekelman