Progressive music

I have been wanting to write a Dream theater/rush style song for a long time, but i really don't know how to. What kind of chords/scales does john Petrucci/Alex incorporate into there rhythm/solos

Awesome man! The thing is,Petrucci is well know for his Heavy Riffage,progressive and weird time signatures,and of course his virtuoso playing

Lifeson is known to be one of the best chord makers of his time,his main style are his effects,and his chord voicings,try to analyse some Dream Theater songs,and some rush songs,learn them,and learn from them,analyse shapes and patters,analyse why does john do that on a certain part of a song or how alex came with that chord

Its just matter of time until you get the prog thing goin on!! But be careful,dont be another Petrucci clone,there are like 28394732982397659328 of them now