That should work fine, all depends on the rest of your setup. The high pressure guage will cahnge with the room temp. Hot weather and a real full canister will read around 1000 and I have seen 1100psi. Cooler weather with give you about 830-850 depending on the guage quality. CO2 turns liquid at 835psi, IIRC. This pressure is the tank pressure itself.
The low pressure guage should not fluctuate once you get it set. It may creap for a minute or so but thats it. The needle valve you use and how many you have will dictate the low pressure. I usually run mine around 20-25psi using up to 3 Clippard minimatics. I believe the JBJ's or some other brand have a set pressure of like 7psi, which is why they don't work well for multi-tank setups. In general, higher pressure means the needle valve will act more "sensitive". I would recommend you set it for 15-20 psi if you have 1 needle valve and don't worry unless something seems wrong.
Yeah, that is fine. That is what my was running when I first connected it it stated 50 and 1100. Though after running for a short while and getting stable it read 30 and 1100. Room temperature effects the higher reading so her in Taiwna dn hot weather I always get around 1100. If the lower reading is too low you will find it hard to keep the bubble count stable. So just keep it where it is and tweak your needle value to get the correct bubble count and you will be fine.
Yeah, I have to set my Azoo around 40psi to keep it stable. Just a heads up--the pressure kept dropping on mine for the first 2-3 weeks I had it. I would come home from work to no bubbles at all. Now all is well and it's running smoothly, but it took a while to "settle in," whatever that entails. It's a good regulator but it seems to have some minor problems when first set up.