OK, I did it. AB testing. SD-1 pedal between guitar and FX8 and I switched the fx8 in an out by using the true bypass feature.
I was able to get them to sound within, say, 90% of each other. With further tweaking, I could get it even closer (I only spent 5 mins doing this)
Here's what I found out.... The EQing requirements are different because with the pedal, the head's gain is higher, which thickens the tone. So right off the bat, the pedal sounded really full and beefy, and had more gain. I can compensate with some EQing to fix that tomorrow.
I think I totally barked up the wrong tree with the global EQing I was doing before. I will tweak some more tomorrow and report back.
I'm also going to Guitar center to see about getting what I need to get the channel switching working. There's another post about that though..
Thanks again to all!
The SD-1 (a real one) is the core drive I used with my vintage AC30. I've had no problem at all getting the same tones with the Fractal model. I agree with what others have said about the Global EQ--no need at all to go that route. Just mess with your drive settings until you nail it. I'd be really surprised if you weren't able to.