I use ferric Chloride at @ 1.5%, Hydrochloric @ 5%, Sulfuric @ 5% I have not measured Ph. I read labels to find the concentration, and add to water accordingly.
in English:
Radio Shack PCB etchant 1:3 water.
Hydrochloric I get at 30% from pool supply (muratic) , and Sulfuric from auto zone, I add to water bringing down to 5% mainly for topographical then a finish etch in Ferric chloride for color.
Vinegar I use alone, for high layer blades (over 400 layers) white vinegar to 1 or 1.5 part water.
I have no Nitric.
Warming speeds up etching, and many seem to be in a hurry and prefer this. I like slow etches, as they appear more even to me. My Swords I use Vinegar 6 to 10 hours, very slow to etch but detail is great.