i use 0.8 if using my mates set and i have 0.8 on my new set at home , the stuff i usually do is brackets for motorbike projects and that sort of stuff, usually around the 5mm thick and under steel . Average around 3mm, anyhow im not experiencing any issues with 0.8 but just wondered if using 0.6 would be a " better" choice , i know 2 lads that build hot rods etc amd won't use anything but 0.6 but they just said personal prefrence..