Milky way project -- Film Choice

After camera selection for the Milky way project the next more important thing will be film choice.
The "perfect" astro film would combine a few characteristics:

1. No reciprocity failure
2. Fine grain
3. sensitive to H-Alpha at 656.4 nm
4. Sold in 4x5 format
5. Fast
   
6. E-6 positive development
7. Handles push processing
   

However there is as far as I know no such film. Fuji's provia 400F is gets 1,3 and 5, and not bad on #2, but is not sold as sheet film, so that kills that idea. So what is left

• Provia 100F
• Astia 100F
• Velvia 100
• Velvia 100F
  
• A Kodak film
  

It looks like Velvia 100 might do a bit better on the red, Astia has a bit finner grain, and I think Provia will push better. I think they will all be fine on the other points. Kodak's datasheets are not as easy to understand as Fuji's, so I will stick to Fuji.

I may have to buy a few rolls/boxes and take them out to test and see what does best.