[Amps] cathode return?

[gdaught6 at stanford.edu]

Gentlemen,

I am in the throes of building a grid-driven amplifier using a tube 
with a thoriated-tungsten filament that has a rather unusual filament 
voltage, and my filament transformer has no center tap.  

I know about the "trick" of using a smallish center-tapped 
transformer to provide the cathode return, where the transformer 
needs to be rated for the DC cathode/anode current.  I am prepared to 
do this, but... 

I have seen designs for using such directly-heated cathode tubes 
which simply attach the cathode common return to one of the filament 
connections.  (The filament connections have multiple RF bypass 
capacitors between them, and to ground.)  

What are the arguments for and against each of these approaches to 
providing the "cathode return"?

73,

   George T. Daughters, K6GT