Josh, have you seen Dave's superb tutorial / article on the EWBS page? You can't get much better than his side-nocks, he's the king of them. There isn't much more you need to know about them that isn't detailed on his article, so have a look on there. The string doesn't bisect the center, however. The groove that goes into the actual wood of the bow tip is only about 1/8" deep - it's no more than a gouge, really.
Two vital points regarding side-nocks - there must be a lip on the horn nock on the bottom edge, and the string loop mustn't be too large.
If they're done properly, there's basically no difference between sidenocks and full nocks. They're slightly easier to use when stringing a bow, but other than that you wouldn't notice the difference. They're historically accurate of course, as we know that the MR bows had sidenocks.
Read through Dave's article, and have a bash. I've not got them right yet