We always recommended mixing our glitters with clear gel (whatever system you use).
Use a bit of foil and decant some clear gel, using a mixing tool with three small scoops will help you avoid waste (you can always add more). Then fold in three small scoops of glitter. You will probably find you need a slightly higher ratio of clear to glitter when it's chunkier.
You then apply the mix to the nail as if applying a glitter gel- it should go on smoothly and helps you avoid any rough glitter poking through and gives a smoother applications avoiding bumps.
I would be happy to send you the instructions we send to our customers as a reference point?
Nicola