Only weird thing i found on managing reactors at the slot level was the slots are numbered based on the full 6 chambers, so even with 0 chambers the first slot in the second row is 9.
Advanced regulator is just a buffer inventory on the left. Then in the middle grid you put up to 9 ghost items. In the right grid you select the slot that the item in the middle grid should get placed in. Compared to the rest of gregtech's machines the regulator is pretty straight forward.
That's the thing. I know what you said. It just never did anything. It was powered, connected, and stocked. All the GT automation seems to work about 40% of the time and then just stop working. I know it has like 60sec sleep periods, but on our server even after total re-installs and config tweaks it would still just silently fail to do things. The automated machines wouldn't even consistently deliver their goods to chests. So on 3 occasions I had breeder reactors basically stop breeding because that regulator wasn't working right.
So either I used it wrong (in which case it's pretty hard to use; I'm not exactly bad at using modded minecraft and I read all greg's posts on the subject) or it just doesn't work consistently. Either way that makes it tough to justify given how expensive it is.