Reddit reviews The Guitar Amp Handbook: Understanding Tube Amplifiers and Getting Great Sounds

EDIT: Re-typing my reply after I've had a chance to reread yours.

It is like the TOP image on your drawing. Just like this, the linked image is "before" on the left, "after" on the right. The AC power connects to both ends of the Primary wiring. Sorry if that wasn't clear before. DO NOT rewire anything about the PT secondaries that go to the tubes.

But, just the fact that you asked, says you really should do more homework before you continue, I think you're rushing this without having a real understanding of how the amp, and AC appliance in general, work.

At the very least, I would pick up Dave Hunter's book, which explains the amp workings in layman's terms. But there is a LOT of recources out there to get yourself more up to speed.

Electric Guitars.

Amp Handbook.

Effects Pedals.

Bear in mind this isn't the end-all-be-all but it's a damn fine place to start and will give you some idea of what can be done with VSTs.

Good luck!

Edit: Just got an email for Session Guitarist from NI which might be worth investing in if you don't play.