I can tell you that Lloyd Walker suggested that I try the fuse both ways in my Walker Motor Drive to see which direction I preferred. He could hear a difference, but I could not. I'd suggest that you follow Lloyd's advice and see if you have a preference..
Fuse Direction for Pass Labs Amp and Preamp
I am going to re fuse my Pass X250.8 and XP-32 with Synergistic Research purple fuses in a couple of days. I was hoping to get advice on a rule of thumb for direction of the fuses. My instinct tells me to start by installing the fuse by the direction of the lettering on the fuses. I am thinking that the direction should be the lettering left to right with the beginning of the lettering facing out of the amp and the end of the lettering facing into the amp. Does this sound right?