Don't look at his hand, look at the tip of the brush.
This. ^
Ed himself even says something to this effect in the video. Don't be concerned so much with the shape you are making, rather the sound you are making.
Like Anthony said, brushes are a very personal thing; no two players are going to play identically. Check out the Art of Playing Brushes DVD. I believe Anthony said that too but it bears repeating.
During one of the interview segments one of the drummers (Charli Persip I think) alluded to the fact that he often changes directions (clockwise/counterclockwise) with his sweeping hand. So just as with any other aspect of drumming, use whatever tool (or technique) you need to get the job done.
Personally, I primarily sweep counterclockwise since that was the way my first drum teacher taught me and also the same way Ed Thigpen demonstrated in his book. Plus, I'm left-handed...but play a righty kit...if I'm going to draw a zero, circle, whatever, I naturally draw it counterclockwise. I translated that directly to the brushes.
As for your questions, I don't think it matters too much what side of the head is 1 and 3 or 2 and 4, as long as it's consistent. If I understood your question, I play like you...with 1 and 3 on the left and 2 and 4 on the right.
Keep in mind though that that isn't the only way to play. A lot of times I'll make a quarter note circle with my left; hitting the same point on the head on each beat while my right taps out the ride cymbal pattern.
I think ballads are especially unique in that there is so much time--and space---to cover. It offers a lot of room for creativity. Not that I pay particular attention to shapes, but I make some sort of figure 8 pattern as well as a variation of the half moon shape you mentioned. I don't have a default ballad pattern. I play whatever fits the tune. If it's a quarter note circle with both hands, or my quasi figure 8 or something new that just comes out when I'm playing. Play for the music.
A couple more brush masters to check out are Philly Joe Jones, Ed Thigpen, and Clayton Cameron.
And some sampling of records...all brushes
Art Taylor on Red Garland's 'Red in Bluesville'
Elvin Jones on Tommy Flanagan's 'Overseas'
Paul Motian on Bill Evans's 'Sunday at the Village Vanguard'
Hope this helps. Good luck