Dose - Recreational Dose?

[joshurawrx]

So, first some background
16s years old (male), average weight. Used to be on daily ritalin (2 10mg pills, one in the morning, one lunch time) 2 years ago.
Started using recreationally 2 years after medical use ended., gone no more then snorting 2 10 mg crushed pills in an hour.

Of course i feel a great buzz, but I'm not sure if thats just it. If I'm feeling the full effects of abused methylphenidate, is 8 lines of 2 10mg crushed ritalin pills enough for a recreational effect?
People have told me to try mixing caffine with it, but i've never gotten a proper recreational dose.
Also I'm scared about tolerance building.

So, i was wondering if anyone out there knows their dosage of methylphenidate, and give a approximate dose for recreational use?
High dose, medium dose, low dose?
Or maybe my 2 10mg pills is enough? and i am feeling the full effects?
Or are their any other ways of increasing the effects? (apart from injection)

Many thanks.