[Amps] Tetrodes working as triodes

[GGLL]

	I was intrigued with the QB3-300 amplifier thread, but regarding other tubes. 
Despite difference in plate dissipation,  what kind of performance can I 
expect in G.G. mode from a 4-400 tube (for an example of tetrode) with  screen 
and control grids tied together to ground, respect the same circuit with a 
3-400 or 3-500 triodes?. With the first tube, should I expect a higher "grid" 
current (that is, control and screen currents added)?. Could be useful to add 
some volts to screen in case of the 4-400 to increase gain, or not worth the 
added work?.

As usual, many thanks in advance.

Best regards
Guillermo - LU8EYW.