If you're using a conventional guitar amp and speakers, it won't work like your amp does, it's designed for full-range reproduction, like the AxeFX or Weir's Eleven rack. I'm also not sure how well those little drivers would fare as the primary sound source for a loud electric guitar. Weir is also using conventional guitar speakers in the Vox cabinets for his stage sound. The line arrays may just be for effects or MIDI or something else entirely.
That being said, when I played rhythm guitar in a band when I first moved to Boston, I used a Roland GP-100 preamp into a pair of full-range JBL Eon 10" speakers, and I really liked the brightness and crispness for rhythm guitar. Keep in mind that Weir was playing through Meyer Sound full-range speakers under the drum risers for a while there.
The QSC K10 or K12 fullrange speakers are what I use, they are 1000 watts, as loud as hell and can take anything you throw at them. The 10" ones have a 90 degree throw, and the 12" ones are 70 degrees. I did a theater gig on Friday night and could've probably filled the house without the FOH system.