I'm done tuning another CME / B-ACD / CUE setup for a customer. They got like 60 extensions and quite busy, on a 2851. This was the 8th hunt-group we set for them. They never had any issues after startup.
At some point I tough a reload was necessary but the problem was with me, eventually all worked as supposed.
IOS ip voice 12.4(11)XJ3 (no crypto) I've left XJ4 for a next reboot just in case.
Again, nice to see, a stable system and happy users.