Its been a long time since I've used Amidol, but what I can tell you is
that I used a formula from Arnold Gassan's book "The Handbook of
Contemporary Photography" which works well, (if I recall the proportion
of Amidol was very high in this solution, as I do not have the book handy
I can't send you the formula I'm sorry ) though when you mix it the
solution goes brown, like its oxidised, though its fine to work with. I
liked the results, though they weren't in my opinion any better than what
I was able to achieve with the Beers developer so I didn't pursue using
Amidol any further. As to the number of prints that you can put through a
solution, it is rather limited. After an hour or less you would need to
mix up a new batch of the developer. Less than 10 prints, probably closer
to 5 or 6. And because the developer starts as a brown colour, a colour
change doesn't tell you much.
These are my recollections, for what they are worth...
Cheers
Hamish