I know the question isn't asked to me, but I have pushed and pulled Scala 50/HR-50, so I thought I'd chime in.
It looks beautiful and contrast rendering responds well in both directions for about a stop. Didn't notice any grain alteration, though.
Was more interested in pulling it to tame the innate contrast, making it more suitable for tripod and natural light based shooting of abandoned indoors - will do again, will pull again
At the end of the day: HR-50/Scala 50 to me is the best film for reversal out there: 1) Not too slow to be ridiculous; 2) Can do IR; 3) Can be pulled gracefully; 4) Nice resolving power that is really noticeable, especially at landscapes and rendering of distant foliage; 5) Affordable; 6) Tough and archival PET base that doesn't deform that much or at all when heated by projection lamp.
Boy, do I miss Silvermax/Scala 160