I've biased my VTL MB-450's many times over the years, but I've only assumed that the bias pots correspond to the tube placement left to right (or right to left). That is, the 1st pot on the left adjusts the 1st tube on the left, 2nd pot to 2nd tube and so on. Since the tubes are staggered you have to move up and down as you go across, but it would be something what I've done below, the first row represents the pots, the second and third tubes. This might be in the manual, but mine may be in a box in the attic.
Does anyone know if this is correct, or if not what the correct order is?