DRUMMER CAFE

Practice 3 bounces for each stroke.  Any rudiment you can double well, triple!  Keep the basic 16th note pulse/stroke like you have been doing with your doubles.

It's tough and doesn't come overnight plus multiple bounce rolls require maintenance.

But you have your doubles happening.  That's great.  I have found I use doubles alot more than triples for rock/fusion (that's basically what I'm into.)

Karem -the obvious answer for all technique questions is simply RELAX, practice and it should happen for you.  

For a smooth buzz I wouldn't compare it to your fast double strokes too much.  Think simply in terms of controlled gravity.    Don't grip the stick too hard, in fact, the looser the grip (within reason) -the better the feel.

Practice loosely letting one stick fall lightly on the head and let the buzz exhaust itself before applying the stroke with the other hand.   You're eventually looking for an even sound between the strokes to the point that you can't hear any accents as each hand begins it's buzz stroke.  

Also, I believe there's a difference between a buzz roll and a (military) press roll and that they're often confused.   My understanding is that a press roll is like a buzz but with a little more aggressive approach and the sticks being played 'into' the head a little moreso than with the buzz roll.    I could be wrong, but that's always been my understanding.      

Kerem -remember,  gear is great -but it's the drummer that really counts.   If your snare drum sounds really bad and doesn't help to inspire you -or can't be tuned properly, try practicing your buzz on a Real Feel pad or even on the mouse pad for your computer.