Welp, there's not so many features to a pressure chamber that matter, really.
You want it to not blow up and not tear your limbs off. That's top of the list.
The two that matter really are max pressure and volume. AFAIR these are graded around 4 bars, which is the sweet spot for casting. Volume of the container lets you cast bigger things, but can pressurize more slowly if you have thin tubing between the chamber and the compressor, or a weak compressor.
You need a single regulator between the pot and the compressor, unless the max pressure of the compressor is equal or lower to the max pressure the chamber can withstand. Then you need none
Agitator is for use with paints and pastes when you use the chamber in accordance with its intended purpose: for delivery of fluids into spray paint guns. It's used when you're spraying a paint that separates easily, has fillers, etc. Metallic coating is one of such cases. It has nothing to do with pressure casting. The additional holes in the lid can be used for some stuff if you remove the agitator, but it shouldn't matter at this point.
Are you having any particular issues? Pressure chambers are really dumb devices, it's not like changing their non-essential parameters influences anything but your wallet.