Just to be clear, I didnt mean to say that phenidone ISNT responsive to bromide or that Bzt DOESNT work with non-phenidone agents. But I've heard (read actually) that the former isnt AS responsive, and the latter isnt AS effective. [\quote]
That's understood from your original post. I've also seen people like Richard Knoppow repeatedly posting stuff like that.
I phrased the question very broadly so that I could perhaps learn something about the principles involved for future reference.
There are two major mechanisms in action of antifoggants. One is electrochemical and another adsorption. Development of a silver halide grain is an electrochemical process; it's like a voltaic cell battery where anode and cathode are shorted. Anode reaction is the oxidation of the developing agent. The anode potential is determined by the developer, concentration, pH, and so forth. These are the reducing property of the developing agents at the particular condition of the developer solution. The cathode reaction is the reduction of silver halide to silver. The cathode potential is determined by the free silver ion in the solution in vicinity of the developing grain. Bromide and organic antifoggants depress the free silver ion concentration in the vicinity of developing silver surface and this modulates the cathode (silver electrode) potential. Addition of Br-, BTA or other antifoggants doesn't change the anode potential (developing agent's reduction potential), but their addition will narrow the gap (called overpotential) so the development reaction will be slower. In well formulated developers, anode potential is several tens of millivolts lower than the cathode potential. This overpotential is most influential on smaller latent images, as large LI doesn't require too much overpotential to develop. Of course, if you increase the overpotential way too much, then the grain will fog, and you'll lose the image-specificity.
The adsorption mechanism is that the surface of grain is covered by antifogging agents. This is at competition with adsorption properties of sulfite, developing agents and other addenda. In terms of adsorption, ascorbate < hydroquinone << metol < phenidone << phenylenediamine derivatives, so phenidone could use a bit more adsorbent antifoggants compared to metol developers, but the difference is small.
In the narrowest sense, I was wondering whether a phenidone-glycin or phenidone glycin-HQ print developer should include KBr in addition to BZT. (although your first sentence raises the question of whether Bzt is needed at all, I prefer having some for the cooling effect on warmtone papers).
I'd use both if you want to keep consistent development time and image hue from the first print to 20th print out of a liter of the developer. Balancing them is also important if you want to get consistent image hue, especially if you tone the print in polysulfide toner.
If you are using an average chlorobromide enlarging paper, the paper will take up a bit more BTA than dictated by the relative concentration of the developer and carryover volume. Also, the paper will release some bromide during development. If you factor these in, you can make a very good replenishing system that lets you print for a very long time without a total replacement of the bath.