Both of those batteries look like they'd do the trick.
I guess you could say the 3600mah battery is about the same as using 3600mah AA batteries wired in parallel. Easier though if you know the current consumption of the MR-1. I have no idea, but with a modern design and good attention to power management, I'd take a total guess that the MR-1 consumes 300 to 500mA of current. So a 3600mA-hr battery divided by 500mA of current draw, means 7.2 hours of record time available from the 3600mA-hr battery.