Re: Rhythm Speed - Right Hand
The faster you want to be, the slower you want to start. The most important thing IMO.
The second most important thing is to GET A METRONOME, if you haven't got one already.
Third, it's always good to record your playing to be able to reflect it properly. Listen to it the next morning, preferably. Don't have anything else on tape, just your own SINGLE guitar take.
I trained to be quite fast (IMO, again) simply with a metronome, without any backing tracks. I think you can't hear yourself enough when training over a record. It's not about training specific tracks, you do that later. I train all down-, up- and alternative picking first slowly, and when it's going perfectly, then up the speed goes. Of course you should sometimes take off and listen to yourself going Master of Puppets at 208, even if it's not perfect, it's fun! Especially when you can actually do that. If you can do that now, I don't know how much you should train more. The next stop could be Slayer's Chemical Warfare at their speed. It's insane! (But I'm working on it, of course.)
Hope I could be of help.