Being a novice user, I have a long way to go before I can actually purchase or test them, I do plan to eventually. Looking through the different items in the ExperiMone series, I noticed the list of concentrations, ranging from the minimal 2.5mcg/spray to the absolutely batsh*t insane 5000mcg/spray with a price range of nearly $4000. How could such a concentration be possible? What would it be used for? 5000mcg is 5mg, correct? What is the average mass of a single spray? How could you do anything useful with such concentrated sprays?
One spray is about 0.15ml, and i believe that the pheromones are in form of solid before, so it is possible to have a high concentration if it is highly soluble. You can dilute them and make your own favorite mix if you have a receipe in mind 
Still, 5mg of dissolved androstadienone in a 0.15mL spray? If I remember correctly, one mL of pure water at room temperature has a mass of approximately one mg. Either the spray in the super concentrated bottle is much larger than a normal bottle, the liquid is supermassive, or there is some sort of technical calculation that determines the mass of pheromone per spray, but the liquid is not actually intended for/cannot physically spray. I haven’t looked up any liquid densities, so I may be missing something obvious.
Experimones in that high range are for purchase by other mone dealers. Its more cost effective for them to go with a extremely high concentration when they make mixes for sale.
So suppose your going to make 1000 bottles of a certain mix for sale. You would go higher in concentration but use less actual mone mixed in the mix you are creating.
For a person using on a personal level…
I get lower concentrations for layering like between 12.5 an 30 mcg depending on the molecule
If I want to mix my own mix in a atomizer, I will buy 30 mcg or better and use that to make a mix keeping in mind that the other added components will dilute the mones mixed.
Tisha