Viewing distance is proportional to print size. Format does not matter once it's past a certain threshold resolution. 35mm is past that threshold.
Your signature would disagree!!

If the image is sharp there is no reason to limit the display size, I'll quite happily print up to 20x30 from a good 35mm neg. On the other hand, I'm very against printing OOF images, I often hear people saying, "It's not quite in focus, but I'd print it up to 8x10...". Artistic focus (holga etc) is a whole other ball game.
. I think you know what I'm saying though - there's not a huge difference, resolution wise, between 8x10 and 20x24 once it's being viewed. People will move in or out. Intimacy of print changes with size though.
These days, I think we need to think a bit more critically about big prints and question the trend.