[Ted Kendall]

I said it wasn't simple - the Dolby version did, however, raise the signal level at the tape monitor switch from the 9mv average of the standard version and eliminate the loading effect which causes a 1dB drop in recorded level when the switch is set to Input.

Angus McKenzie published some modifications which addressed these problems around 1970. These and re-connecting the VUs to the monitor output may be a way to go, but readings will be dependent on the monitor gain setting. Offhand, I can't remember whether it's possible to connect the meters before the gain control without additional buffering.