Did some more fine tuning and had a good test. Went up to 52m or 170ft with a solid position hold and back. All of this flight video, except the hand launch and hand landing has been done in crawl mode, and baro hold. The position hold performed very well, even when I got as close as inches to a tree top. I believe I am getting very close to my target of having a precision position hold which can also perform at higher altitudes. The next step is installing a front sonar to avoid contact at closeups. Then, I will also install a GPS as a backup system.
I am pretty confident that the system will work in even higher altitudes but I cannot test that in my neighborhood park. Need to get out to the fields.