Hello , actually i want to use 3os lamprey circlet, for GF barb merc.
Am ask if better to put on it 3 jewel 15ias/Xed or 2jewel 15Ias/Xed with 1 Jewel 30 Fr ( and ed demon or other stats)
Or last option 2 Jewel 15ias/Xed + Cham ( for can not be frozen).

Thanks for all advice!

Go cham if you use coh. He'll have max fire res anyway and life leech from coh will help with sustain.
There is no item setup to protect merc against full spawn of hydras, he need to attack and leech life to survive.
The best defence is attack in this case

Thanks dude, yes i use CHam + 2 15ias/Xed , it s usefull