One thing that I would add to all this is to raise the temperature of the developer - I believe I get one paper grade from 70F to 85F. Another thing is Potasium Dichromate or Benzotriazole. Adding these will restrain the development of highlights allowing for greater contrast.
Oh yea ... Being a cheapskate, any thing that costs as much as Amidol (even the cheap Chinese stuff) needs to be good for more than one shot. I have nursed Amidol for weeks. It has a lot of capacity and if stored in a full amber glass bottle, I can get several printing sessions out of it. I will admit that the Amidol-only charactaristics fall off pretty fast. It starts to act like Dectol after the second session.