[Amps] Phase and amplitude of 2 tube amplifiers

[Conrad PA5Y]

I am going to attempt to use 2 identical monoband tube amplifiers to generate CP but before I start I have a question. The 90 deg delay for CP comes from the array orthogonal physical boom separation. So the amplifiers must be in phase at the outputs.

I presume that this has been done in broadcast applications and I would like to know, assuming everything is tuned correctly how close the phase likely to be?

I have line stretchers for the inputs, I have extremely good phase matching on the Wilkinson splitter and 2 identical directional couplers that I have tuned for good phase and amplitude matching. I can also measure the relative amplitude and phase of the 2 amplifiers accurately. Small phase and amplitude adjustments are ok but I have no idea what to expect with tube amplifiers.

This was not really planned but a 2nd amplifier became available, so I thought why not? The tubes are becoming scarce so this way I can be a lot more gentle on them.

Regards, Conrad PA5Y