Just to give feedback since I had trouble with 2.29/2.30 sonar alt hold. Testing back in my much smaller area I found that with my original stock sonar (1200) was working much better. It was holding pretty much like 2.24b/2.25 although I still have some noise when looking at the log. However my grass is fairly tall and I think that may be giving some of the false readings. The sticking for long periods of time at 60 cm problem seems to be gone. The quad stayed at 4 to 6 feet for long periods of time. At higher altitudes it was also holding pretty well, but it wasn't perfect. However I'm a little suspect of my 2 layers of black felt on the pressure port and will try my original cotton port cover to compare the performance. I'm wondering if white felt would be a better choice in the hot St. Louis sun (90 degrees or so.
Loiter worked much better also. My circle of error seems to be 5 meters or more, but my small area is not easy to test in. Trees on all sides force me to abort testing quite frequently. Anyway 2.33 looks very good to me. -- Thanks Jason and all.
I will try the 1260 EZL0 sonar next to compare performance and see if I can remove some of the sonar noise and test on concrete.