I notice there is no data for load resistance for a 01A, but I suppose they were never inteneded as an output tube? If used for that purpose, would 5 to 8k be a resonable value?

The '01A's plate resistance is 10K ohms. (Click on "TUBES" above.)

Rule of thumb: the opitimal speaker load impedance should be about half the plate resistance, so let's say 5K.

For max power transfer, the load resistance should equal the plate's. But other factors enter in, so go with 50%.