Well, I hadda top off one of my Great White tanks this afternoon.
So, I ran the Box with the cover on for about 20 minutes, the temperature was 126° from ambient of 73°. I then continued without shutting it off but sans cover. It ran for another 16 minutes and the temperature was 124°. This without any extra fans blowing from the front, just the larger computer fan that I installed when I installed the radiator.
No radiator was used.
With a variable temperature, a 2° delta ain't much. As you well know, it does run much cooler with the radiator, so my next fill I will do the same, run with the cover, then without in the same top off session.
The Great White topped off in 36 minutes from 4,000 PSI to 4,300PSI, or ± 8.33 minutes per 100PSI. When filling around 650PSI is runs
± 9.03 minutes per 100PSI.