Steve Smith told me that all sailplanes would climb and cruise better when the CG was at least 80% of the allowable range. I found out the Genesis-2 wouldn't climb in a weak thermal unless the CG was 90%. Fifteen years ago, I rigged up an in-flight CG Shiffter, mainly to investigate the handling of a flying wing with an extreme aft CG. It consisted of a 10# weight inside a 5 foot plastic pipe with fore and aft cables.............blue handle and red handle! Found the handling got a bit more pitchie at 90%, but I was able to climb with most ships. BTW, I found pitch control by shifting CG, didn't work, but aft CG was essential to get the G-2 to go up in a 1 to 2 knot thermal.
Random thoughts from JJ