I have an old Silverstone case with about 6 of the old style 3,5" drive mounts and 3x5,25" bay. Originally I had a Samsung 1TB drive in it (which is still kicking around somehow pulling torrent drive duty) I remember it being louder in that case then in my new one. So I’ll have to test it out. If i can get my hands on some rubber bearings and if they help any at all.
I am not planning to go that big on storage for now tho. It sounds like serious work. I am doing this so I can be more comfortable. Aside from updates, I want to dial it in once and forget it unless I need to touch it.