Homebrew PCBs

Having read up a bit on CuCl2 etching, I can see that there are 
quite a few advantages to using it, especially versus FeCl. I'm 
wondering, though, about how critical the chemistry aspects of it 
are to getting good results.

How difficult is it to determine that you've gotten the 
concentrations of the various chemicals involved correct? How 
difficult is it to maintain the etching solution in good condition?


Thanks, Bob