i use to use a light sorc, im guessing ur doing coutness runs with her, i would suggest the following gear if so:
Shako
Tals armor
Arach sash / tals belt (u choose)
Magefist/Frosties (if you need mana)
trecks (best you can get)
occy
spirit
2x soj
tals amy
with that setup, i had base mana, and was still able to last long enough to kill countess (ok maybe not base i really dont remember, but i know i didnt waste much in it)
as for your merc, infinite is always popular for an a2merc, but for a cheap and effective move, go with this:
Vamp gaze
Levi shell
dual amn'd bonehew
with that setup your merc will never die doign countess.