I use 55# Samurai spinning and #30 Fireline conventional and never gave it a second thought. If there are no obstructions (and you protect your finger) I don't see why #40 wouldn't work. Just curious, what rod are you using to throw such big stuff?
thanks guys, someone just told me i needed t go bigger, in line i wasnt sure so i figured i'd ask. I am a rod builder so I have a few rods, GSB1321M, and I got a rogue that can handle the 4 oz ones. Lookin into a CTS 1 piece too.