I`m interested in learning how does the high pressure gauge read as the pressure drops on your regulator.
I`ve read on the forum from time to time by a few that once the pressure gauge starts to show a drop in pressure it`s not a gradual decrease in readings, some claim it drops from approx 700 PSi to zero rapidly with no in between readings.
Personally my experience is different.
It is likely to be more gradual at cold temperatures, as in the drop will be observably more so, in my experience. Before I got into this hobby my co2 usage was in homebrewing and I had my tank in the fridge. I could notice the drop and have ample time (days) before I would take it to refill. As my aquarium tanks are sitting at room temperature once I see that needle move I usually take it right away to avoid going without co2. Again, this is probably subjective though, since I only pushed beer at around 10-15psi and in the aquariums I have it usually set to around 25-30 psi which would give me a less gradual drop.