I think I'll stick to best tool for the job. It remains to be demonstrated that a direct gate input will perform worse than the closed loop version as applied in Guinevere's plate load circuit.
We're looking at another CCS for the cathode load, but that one is a drain-end rig instead of the source end as applied in plate load apps. Actually, if it could be easily arranged to deliver + and - voltages at the same time, a pentode would make an acceptable CCS. I like the heaterless action of the MOSFET's for this level of experimentation.
Low voltages do have their attraction.
regards,
Douglas