So this isn't quite as big, but if this helps give you any idea about it.
Also don't make fun, this was done as a joke and is part of a web series indie project I was a part of.
Lastly, this is totally digital, not film, but assuming the OP is either wet printing or having a high quality drum scan done and printing from scan, the results should be better than this.
A 24x30 print I have.
The pelican case is a 1510 (or 1512) for size comparison.
And these are close up cell phone images of the "grain"
I shot both with and without the stupid flash.
So even with a 21mp (which makes a 25mb RAW file which is probably 50mb TIFF if that helps at all for anyone scanning). There is great detail, so yes there will be grain but certainly not terrible grain and the detail will be there with a film print. It won't be the same as the detail of a 4x5 negative. But I'm sure the print will look nice enough for a museum/gallery, it does depend on original film too of course.
Anyway I'm not an expert, this is the largest I've ever printed, most of my X by 30 prints are from 120 and not 35mm. I haven't gone to 60 yet, but now you have challenged me haha, I think I'll make it a panoramic though, 20x60 sounds nice.
~Stone | Sent w/ iPhone using Tapatalk