Hi!
Nitro is not difficult to obtain here in Europé ,at least not here in Sweden.
I think most of us use at least 5% in our fuel (mix my own) as nitro makes most engines run more relible at idle and the top speed is more easy to set using nitro. There are eceptions with webra, SK, ASP and MVVS engines that run good without nitro but even those engines run better (more reliable) with 5% nitro.