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I recently purchased a Gezten G50 CC tuba with a compensating 5th valve. Does anyone know where I can find a fingering chart pdf for a compensating CC tuba?

To the best of my knowledge there is no such thing as a compensating 5th valve. The G50 is just a regular 5 valve CC tuba and will use the standard 5 valve fingering chart.

The compensating system and the 5 valve system are different systems that manufacturers came up with to overcome issues of a non-comp 4 valve instrument: bad low range intonation and no access to the note one half step above the pedal fundamental (C# on the CC tuba). Having a 5th valve means you don't need a compensating system. You have access to all of the notes between the 1st and 2nd partial, and intonation will be more manageable than a non comp 4 valve instrument. Same thing with a compensating instrument. You have all the notes you need and have improved intonation in the low register compared to a 4 valve non comp instrument. Since both of these systems solve the same issue there is no need to include both of them in the same instrument.

Years ago I saw a 5 valve compensating eb tuba. It was basically a standard compensating eb tuba, but with an extra 4th valve on top with the first three that acted as a non compensating 4th valve when the normal 4th valve was engaged. Basically, using the normal 4th valve and the added 4th valve at the same time would produce an in tune low F on the eb tuba. In other words, this was somewhat of an attempt to make an Eb/BBb double tuba. When the normal 4th valve was depressed the tuba was like a noncompensating 4v BBb tuba. This was a one off job and I don't think anything like this has ever been produced by a major company.

Unless you have some crazy custom instrument, there is a 99.99% chance that you have a standard, non compensating 5 valve CC tuba. This chart would be a good starting point before you figure out the exact fingerings your horn prefers. https://norlanbewley.com/bewleymusic/tu ... e-cc-tuba/

This ^ There is no such thing as a 5-valve CC compensating tuba, if you are talking about the Blaikley-Boosey compensating system we associate with British tubas and euphoniums. But here is what the 5th valve does:
1) on older tubas, it had longer tubing so that it functioned as a substitute for 2+3.
2) on newer tubas and converted tubas, probably including the OP's, it is essentially the same as the 1st valve with the tubing pulled so low F 4+5 will be in tune.
Remember, music is geometric, not linear. In an equally tempered Western diatonic chromatic scale, each half-step is 2^(1/12) longer as you go lower, so each octave is half the frequency which requires nominally double the tubing. Without doing all the math, this means that, for example, the valve combination 1+2 needs marginally more tubing than either 2nd valve alone for the first half step or 1st valve alone for the whole step. This is why the first valve slide is usually routed where it can be manipulated by the left hand on a conventional tuba. And so it goes for each note that requires a valve combination. I even have the upper loop of the first valve circuit on my 3-valve sousaphone made as a movable slide in order to get 1+3 in tune, since it requires a good pull.