I think maybe 1/2" to a inch above your holes would be ok.
Everclear you can get at the liquor store, if you are not old enough your will have to have your parents or someone else pick it up for you. It's really cheap, only $3-4 bucks for a 1/2 pint, and it does not smell as bad as other stuff might and I wasn't sure if you were using alcohol or Acetone (Which can smell bad). I just noticed you are in Brazil, so they may not sell this there? It's 190 Proof alcohol.
I think you might be ok with the alcohol though, 99.9 percent is damn straight alcohol so you are probably good to go with that! Everclear is only 95% so it would not be as good as what you already have anyway, but it might be cheaper and smell better though.