Gordon,

Yes don't.  Those vacuum fats have plat to grid capcitance and if not neutralized
(or even if it is) it will take off and get unhappy.

If anything lower might be the thing.  The key is you need enough RF grid voltage
to drive the tube but likley less than the total bias needed to get plate current.
Some tubes gt really unhappy or terribly non linear if they see grid current flow.

Grounded grid has some of the same issues but offers a naturally lower input
impedance and a bit less gain.

Allison