I recently was given an RSST & rda. What I was wondering is I do not currently own a MECH, I have a iTaste VTR and a couple ego batteries, should I use these on my VTR or should I wait till I get a MECH? If I can use these on my VTR, what would be the best/safest set-up? I got to try a Grand Vapor rda the other day and would REALLY like to use this one I was given.