It sounds like a mic ratio issue, try and work on getting your ratio right and you will find a solid color.
NSI color powders are beautiful to work with and provide great color, you just have to get the mix ratio correct but this goes for any color powder.
Make sure you pick up a bead the exact same way each time, use same pressure when wiping extra liquid out, use same amount of time in powder to pick up bead.
Use your brush to get the correct liquid amount in your brush, you can either wipe it less or more, dip it less or more, depending on what kind of bead you want.
yes, you can dab your brush on towel after picking up the bead but this will contribute towards 2 things.....1, putting more vapor in the air (making the smell stronger than it needs to be) and 2, wastage of product, why pat it out and waste liquid, when you can do the same in your liquid dish and keep that product in there so it can be used.