I think if you took a DI before the amp using a complicated effects set up, then having an SVT on stage to monitor would be a bit silly! Maybe not if it's mic'd up though.
I always struggled with this - no-one liked my DI from the Peavey combo 'cos it's noisey, no-one liked the DI from my pedal board because it needed a lot of top rolled off, and some bass boost etc, basically what I was doing witht he EQ on the combo. The only way to get a good sound through the PA was to take a DI from the amp, roll all the high end off to get rid of the noise, and then mic my guitar combo for the top end. It's a shame some engineers are not that obliging!