Two suggestions on the list, 1) You suggest 1/25th shutter at 24p -- defying the hallowed 1/50th rule. Is the motion signature going to change? Or is it not perceptible? The comment suggests as long as tripod is used, no advantage to 1/50th guideline. 2) Shooting up to ISO 12000? Wow! I don't even like what 800 looks like!
@Ralph_B Great tip about ISO settings, I did not know that...
@brianluce What don't you like about iso 800? I use ISO 1600 a lot and sometime 3200 If the exposure is set ok it's no problem, if you underexpose you get problems.
The motion looks a little different at 1/25, but not radically so. Most of the time, you'll hardly notice it.
The bigger issue is simply using the right tool for the right job. If you need to get more light into your camera, there are a number of different ways to do it. That's what my post is about. Experiment with them. Become familiar with them. Under different circumstances they will all come in handy.