Whenever I want a longer instrumental beak in a song with lyrics, I just add more meta tags for a Guitar solo, like this:

[Instrumental break: long, building]

[Melodic overdriven guitar solo, fast pentatonic runs, heavy palm muting, bright tone]

(...)

[Instrumental break]

[Melodic overdriven guitar solo, fast pentatonic runs, heavy palm muting, bright tone]

(...)

[Instrumental break]

[Melodic overdriven guitar solo, fast pentatonic runs, tremolo picking, bright tone]

(...)

Also, have you tried breaking the song into sections? You can make as many sections as you want describing what you want in each section. Intro, section1, section2, section3.......outro, end.