Also anyone here got droprates for Uni 22, 23 and 25? Spent over 10m gold already and I only have 2 of those .-.
I spent over 45 million gold to get Uni 23, so you can draw your own conclusion from that, I got Uni 22 rather quickly though, maybe 10 million gold in, or so. They are likely a "less than 1%" drop.
You will always get a random result from a pool of items, depending on what Rune and combination of Reagents you use. It's entirely possible to not get Courage tonics many times in a row, so just be patient.
The 2 Items are a very low droprate, 1% or lower, definitely, because it wouldn't be true Nulgath farming without a couple of those at the end.