I listened to g610 audio clips you posted and they are amazing, it is a real saturation as described here by dpclarkson. And it's cool to have a pre including this in just one instance. +1 for Gemini! And it is a 610, the one used in a looot of USA recordings in 60s, I feel happy
Anyway the tubes boosted by Michael does this thing too. Please correct me if I am wrong but I think Michael got it perfectly.
In that case driving "drive" (sorry for tautologie) doing it well, but too much will makes anything sound thin with unwanted transients. But adding a little will make really interesting results. Especially on drums.
i made a set a while back called tube fm 4 that i think can do some pretty obvious distortion/compression/sat and other crazy effects. a lot of the stuff in it is fairly extreme and maybe better suited for sound design in some cases rather than subtle mixing (though some can do that too).
I actually made a load of distortion presets using 20 kernels last year but never got round to completing the pack. Some if them came out very distorted. So high saturation i think could be possible but not mega.But I got so busy with being a musician again that I didn't finish it. Now I have massive list of things to nebulize but don't know what to do next......