Chain summoning 39-60 questions

[renegadeofunk]

First noob question: below 50 do I use fire or earth (w/ DS?)?

Second: Since the fire pet's usefulness gets gutted after 49, is it viable to just chain cast it at 50-53+ mobs (both old world and Kunark) or would the 51+ earth pet with my DS/DW daggers/burnout be more efficient in the long run?

I'm basically just trying to get a sense of what playing will be like if I keep leveling my 24 mage. I do like chain summoning so I hope I get to use that into Kunark in some way. Thanks for any help you can provide!