I'd assume that you want to back off about as much as the Peak to Average of the signal, so you need to know that first.

It would be great if you could get the good bits scanned and available on the internet. The Internet Archive takes hard copy donations, and will scan them and throw them up there. There's a bunch of electronics texts there already.

I have a bit of a problem.

I came across this
https://www.highfrequencyelectronics.com/Jan10/HFE0110_Marsan_Part1.pdf from the 2010 High Frequency Electronics on measuring sub 1dB NF parts. I haven't scrubbed through it, but it might be applicable. there's a P2 as well.

I think that's a nice piece of wall art. Connected to a patent of some sort possibly?

You've probably figured this out by now, as you're a smart fella, but at one point, Keysight has a Noise figure uncertainty calculator on their website that would estimate how much error there was in a measurement, given the VSWR's and the ENR performance. That might give you some direction.

You've probably figured this out by now, as you're a smart fella, but at one point, Keysight has a Noise figure uncertainty calculator on their website that would estimate how much error there was in a measurement, given the VSWR's and the ENR performance. That might give you some direction.

Your post is a bit unclear.
I like this note from Marki Microwave for Couplers and directivity.

https://markimicrowave.com/technical-resources/white-papers/power-dividers-directional-couplers-primer/

I got it sorted out. Not a transistor at all, a nice high power RF resistor.