@d3fn So my results were pretty consistent when running the same applications at the same time. The M1 Pro consistently showed an extra 2 hours of battery life compared to the M1 Max. The M1 Max also had a consistently higher power draw as well in terms of wattage so the difference in battery life makes sense.
All I did was charge both to full, put on the same documentary on YouTube, and let both run for an hour at half brightness. The M1 Max definitely used more battery and I'd say the M1 Pro could probably pull of 12 hours of battery whereas the M1 Max is likely to be in the 10-11 hour range.
Still conflicted on which to keep!