Most people (myself included) just go 5/5 Hyoton, since the tools are cheapest (and it has the benefit of being ice if you are doing a MAB build with beyond atma). If you want to have two, I'd recommend Katon over Raiton since Hyoton will lower resistance to fire and help that out. But honestly I think it's just simpler to do 5/5 ice.
Formerly of Lakshmi, now in Asura
FFXIV: Kagu Tsuchi