I made guide about that a while ago when the liches first came out. It was before elemental rework so its quite outdated now. Ppl ask me questions or quote that thread in other posts so i guess i can make an updated version (since the old thread is archived).
My intention was to pick the best elemental base for each weapon accoridng to its type (either high rof AR or slow hard-hitter), its IPS values and having some build variety if needed.
Now some explanation
Im aware im old fart using corrosive+heat since the new meta is viral+heat but...
Having heat as base elemental