Top o line quad pairing is without a doubt the 400 or 500 - if u can find one & ( if ur staying with mesa power).Over the decades Ive ran many quads thru a mesa 2 90 and strategy 400 and the 400 crushed the 90.It doesn't get any better.Amount of volume has absolutely nothing to do with it at all.
A mesa 2 50,2 90,295,etc all go to loud.
Where the 400 and 500 take the lead is in feel and authority and pure agression in tone. That where the big boy IRON out shines the others.
Back in the late 80s I bought my 1rst of many quads,a 295, and 2 cabs from thoroughbred music. I thought that sounded pretty darn good for a teenagers rig...until I stood in front of strypers Michael Sweet and Oz fox's quads,400s and cabs at a show one night. That was nxt level eye and ear opening for sure.ill never forget that.
That was also lesson #1 for me in how iron makes a big difference.