You wont be able to get high until the blanket effect from the subs wears off. I think this is after around 72hrs. maybe sooner for some people
I do. Yes, it builds a tolerance cross applicable to any mu-opioid agonist from morphine to heroin (diamorphine) to Oxycodone. See the sticky thread that I wrote in this subforum for a guide to equivalent doses between Suboxne and common opioids to figure out how bad your tolerance really has gotten.