May I suggest buying an old freq counter. We have seen demand and price for these go down in last few years.
Less than $100 for a good one. We have some sitting on the shelf at the radio shop for months without selling. Possibly more people are using the nice cheap Spectrum Analyzers rather than a stand alone Freq Counter. I suppose that is another option.
I use a Service Monitor that is calibrated to a GPSDO, but these things are expensive. (I think Service Monitors are worth the prices though)
Heath had some nice counters and even old HP counters are cheap. I have both.Any instrument is only as accurate as their internal reference oscillator but that is usually plenty good for radio alignment.
Some have facility for an external reference, which can make them more accurate.
Consider one that meets your frequency requirements. Heath had nice ones that will measure well over 100 MHz for FM radio work. However most freq counters need a sizable input to work, some are more sensitive than others and some have variable inputs with attenuators. Spectrum Analyzers are much more sensitive.
Usually I use a S9 signal for the input of radios that I am working on. S9 is -73 dBm. My HP counter will not show a freq until it has a -20 dBm signal and my Heath will read a -40 dBm signal (at 30 MHz). No where near S9. The cheaper counters are probably less sensitive. The cheap spectrum analyzers can read signals far below these. I do not have any of the newer cheap SA so possibly someone may comment about the practicality.
Also, as I recall, the output from your venerable Hickok can be quite low at the higher end of the frequency output, If you put the RF amp inside the Hickok case, it may help the high end output. There should be plenty of room in the case.
I used two of the type of 50 ohm amps you have posted to amplify a 400 MHz signal that I needed. I used a SAW filter to limit the input to the amps to get the desired freq. It worked very well, I got about a 40 dB gain that I needed. If there are undesired more powerful frequencies on the input to any amp, it may overload the amp and the amp may not amplify your desired freq enough..