You'll possibly find old posts of me whinging about the annoying nature of Vintage 30s speakers, but honestly now I am regretting selling a Mesa/Boogie 4x12 that was loaded with them. That thing sounded amazing with my MarkIV. So edgy and sizzling when using the graphic EQ, awesome top-end crunch and had the chug in the bass and lower mids. When I can afford it I will buy one again.
Oh by the way, I use the Lead channel with the EQ for a heavy rhythm crunch sound, then turn the EQ off for a lead sound. Or maybe use something in the effects loop for a different texture for lead sounds.