Interesting approach but I'd want to run the test on a cold rainy day with the lights, furnace and TV running. Even then I would double it for bad weather and the fact that once you have solar, you tend to relax and use more power. I feel the same about the battery, the freedom the excess gives you makes it easier to keep it in balance.
The other thing is it takes a while to get your routine down to the point that you know how much power you use daily like Roy does. It took a few years of boondocking and paying attention to the morning resting voltage to get a handle on how much power just the trailer uses. That's nothing compared to the inverter, it really sucks the power. Our day to day changes a lot. Run the little AC and it spikes that day, use the pie irons instead of the cook top and it slumps. So we generally use up to 200 Ah a day but that's growing still.
