I'm running 15mm on stock suspension and the wheels sits exactly flush with the arch and catches sometimes when I hit a deep hole fast. So I'm guessing you wouldn't be able to go that wide. Probably doesn't help you but just my 2 pence.
Thanks for your response dude, appreciate it
Im thinking 8mm, 10mm or 12mm (absolute max) to avoid any rubbing but cant seem to find any solid answers as to which one i can squeeze in there to give the widest stance possible
Hopefully someone will be able to confirm or feedback their findings