Much more success later!
We've had the arms locked on ALS and held off resonance for more than 2 hours now. That's good. We've done several trials of locking the PRMI and trying to reduce the ALS CARM offset. Once we were able to get quite close, but we never achieved zero CARM offset.
One big finding is that when the TRX and TRY are about 0.1 in the coupled-cavity case, we start to see real length information in the 1/sqrt(trans) signals. Q will edit this elog, or reply to it, with the data that he has collected.