I'm a bit confused as to the question, but I'll answer anyway, because that's how I roll
The only 'fundamental' difference between a rack setup and an amp-head is that a head has both a pre-amp and power-amp section in it. That's really it. For specific rack pieces vs. heads vs. etc, you'll have to get people who know a lot more about these sorts of things... i.e. I don't know how similar/close to a recto pre-section the Recto Recording amp is (actually, I don't even know which model of recto it would even be closest to, never played one in my life ;P) If they're truly identical, then they *should* sound essentially identical to the head, save for what little variation you'd get from different output levels into the power section, cabling, etc.
You don't necessarily have to run the pre directly into the board, but it's at least an option to try. Most people still seem to prefer micing up a nice cab, so it doesn't really matter much here, but if the whole point is Direct recording, pre-amp choices tend to be a bit different than if you're planning on running it through a cab or four.
Um, I'll stop rambling now, because I'm still not exactly sure what you're asking