Ok I can see I was a little offending, but trying to learn something off youtube, when all of us here have paid tons of money to extend our education, was and still is an itchy spot.
I'm sure that as a trained tech yourself you wouldn't like people telling you they've learnt your art off youtube, when you've struggled and gave both your time and dedication to this. And reading your first posts, as Willowrose said, it was quite unclear what you meant and therefore easily mistaken for a non-professional.
However, since I can now understand both your problem as well as your technique better, here's my advice.
You apply the tip and build your acrylic enhancements.
So far you have been airbrushing. I have heard of it and seen it, although never really used it myself. However, I had looked into it a couple of years ago and the thing with airbrushing is it's using dilluted acrylic paint. Not gel polish. Gel is too thick in consistency to even be able to be spayed, not to mention it would probably clog that air-gun. So what's the biggy, right?
Well, acrylic paint as well as normal polish is a soft paint. It will move and shift in a molecular (did i say this correctly
?) level. Gel polish and therefore topcoats are supposed to be stronger than that. However, they won't hold a single day if what's underneath them moves and shifts a lot. They will crack, peel and chip. Would you apply acrylic on top of airbrushing? NO, because it's not strong enough a base to hold the acrylic. Same goes for gel; even if it's gel polish, it still contains gel! So that's problem one.
Problem 2 is that even gel top coats (any kind, matte, shine, non-wipe) are not strong enough to hold rhinestones. For rhinestones there are a couple of different solutions, both work just fine for small stones, just the one for larger though.
So for starters, I'd quit using your gel top coat. At least not with airbrushing. It's ruining your system. Either carry on with airbrushing as you did before, or invest in a full gel polish system (base-colours-top coat). It can be pricey, trust me we all know that.
After your acrylic enhancements are finished, you buff the nail to make it rough (not unbuffed as you said, and not too buffed to be shiny), apply 2 coats of gel polish colour and then your gel top coat. No base needed when applied on enhancements; base is only for natural nails.
By the way, being trained in a reputable salon doesn't really mean you know gels and it certainly doesn't cover you with insurance. Especially if they taught you that mixing systems (like airbrushing and gels) is fine...!
If you really want to invest in this, getting a gel refresher course is not a bad idea, since you obviously lack some basic (gel-related) knowledge here.
For rhinestones:
1st way, finish the enhancement, colour and top. Buff the nail (even if it's gel polish underneath), just the spot you want the rhinestone to go. Apply nail glue, place your rhinestones, then (gel) top coat, or whatever you were using. They won't come off easily.
2nd way, get yourself a pot of a extremely non-self-leveling gel (hard gel), like Bling On by Akzentz, or Gummy Jelly by Enailcouture, and get also the relevant company's no-wipe top coat. Buff the nail as before. Place a bead of the gel, place your rhinestones on it, cure, top coat and cure. Enailcouture has a different procedure but you get the picture. You will need clippers to remove them
Here are a couple of videos, for Akzentz and Enailcouture
