I am currently powering my extractor with 8 hydrokinetics. They feed to a 32 Belt CVT and then to an 8 belt CVT to run it all full power, all stages.
This is a great accomplishment (that also looks and sound great in-game, by the way). I ran a similar setup for a while. But I have to say, that this is not "full power, all stages" as you say. This is minimum power. During my experimenting with the extractor, I have yet to meet any upper limits as to how much speed the extractor can use. And more speed makes a world of difference. My current "working" setup is two pulse jet engines combined, and an automatic two-second switch gearing on a CVT. By a rough estimate, this is about a 100 times faster than the hydrokinetic setup.
It's fun experimenting with rotary craft.
My next upgrade plan is to start experimenting with ReactorCraft, but I have to admit that I am a little intimidated by the complexity of that.