I know this might be general knowledge somewhere, but...

We would like tips on making Bordeaux Mixture. We found some tips on
ratios thusly:

* General: CuSO4 100g / Ca(OH)2 100-200g / H2O 10l
* Allergic to Copper: CuSO4 40g / Ca(OH)2 120g / H2O 4l
* Young: CuSO4 10g / Ca(OH)2 30g / H2O 4l

Are these ratios sound or not?

Also, we would like to know the whole chemistry behind Bordeaux
Mixture, because from what we know:

* Ca(OH)2 dissolves at only 0.18g/100mL of water.
* The CuSO4 and Ca(OH)2 react to create Cu(OH)2 and CaSO4, which are
both insoluble (while leaving a excess of Ca(OH)2 as well).