I've had Retro's since '04 (luv em) and just bought a set of new ones with the 'clew cutout' and came to the same conclusion as you regarding using lower grommet
(see your quote under)
WHY, is it that using the lower grommet seems to make the sail much more stable
I have my boom just above the middle of the cutout so the top grommet would give the better boom angle but for me the lower one makes the sail feel so much better.
Rogers quote 27/7/08
I didn't like the reduced boom length at first, because I've never liked battens that cross through the boom, but once I got used to the shorter boom and started to use the lower grommet only I have changed my opinion on this.