I'm curious why you want such fast film. My experience with such fast films have been disappointing.
I used Kodak Royal 1000 in a Nikon F3 when I was first going out with my girlfriend (now wife of many decades). I regret using this stuff on pictures that I find significant in my life.
The grain has the texture of road gravel. Colors are washed out. Contrast is chalk and soot.
You really play into the weakness of film, trying to shoot in such low light with fast film. This is the land where digital excels.
My other big regret in my photographic experience - failing to use fill flash in bright sunlit shots. For my girlfriend's graduation, I used Kodakchrome 25. It was a bright sunny day - too bright and highly directional light. The shadows are detail-less, and the black gowns and caps are just a black blob. I should have, could have used fill flash, as I did have the flash unit in my bag.
A year ago, I tried Cinestill 800, based on the glowing reports about it here on RFF. This is tungsten color balance movie film. If you want to shoot it in daylight, you need an 85B filter. Outfitted with 85B filters on my lenses, I brought it with me on a trip to Canada to visit the folks. My father had suffered a stroke, and my father in law has metastatic cancer. Cinestill has one fatal flaw: a lot of times the remjet is incompletely removed, leaving long streaks that last the entire length of the film. This happened to me, and the entire roll was useless.
If I could go back in time and kick myself - I would do so 1000 times over. But, we can't go back in time. There are no retakes in life. If you want to use film, use the one offering the most reliable, best image quality.
In penance, I shoot film of ISO 25 (Rollei 25) to 160 (Portra, sometimes as fast as 400, depending on what I have left over). I also carry a flash unit with me. Either a good powerful electronic one, or a bulb flash with M3 or #5 bulbs (even #11 for large areas). Those shadows will be lit!
i would say get a roll of super fast film. Shoot something with it, and then judge for yourself. It may not be very satisfying.
My experience with it has been disastrous.