1) (glycerol in the stock solution) Unfortunately, you won't know untill
you try it. I had some fragments of my pet protein that wouldn't crystallize
at all without glycerol (in the 10% range). I have also seen it interfere
with other proteins.
Remember to add some glycerol to the well after mixing your drops so that the
drops will equilibrate to approximately the expected concentration.
2) Fred Richards at Yale has a nice difference matrix program.
Phoebe at vger.niddk.nih.gov