Painting & Dusting Gumpaste Flowers

What’s the best technique for enhancing the colours of your gumpaste flowers? I tried dusting some gumpaste calla lilies using Wilton’s petal dust (I believe its Wilton’s petal dust) but the bust did not stay it was just falling off. I mixed the dust with some clear alcohol, not too much as I saw a video on Youtube from Edna where she stated not to add too much as it will be grainy. Nevertheless, I added a tiny amount (clear alcohol) to the dust and the mixture was in fact grainy. Therefore, I am not sure if I did something wrong. I tried painting it again it was grainy/sticky and not adhering to the flowers, so I am wondering if this dust from wilton is not of good quality. Is it the brand that counts? What is the difference between pearl, petal and luster dust, especially when using it for gumpaste flowers? What brand of petal dust is good, I am not sure if Wilton’s brand is good? I think I saw a few posts where you can mix your chosen type of dust and also gel or paste colours with vodka. Any suggestions will be appreciated.