For AT runs, and indeed most MF runs, BC can be left off. It saves the frames of casting it, but it also saves changing skills on your CtA switch, which makes running much more comfortable and removes a possible frustration. Your numbers are right, so it's up to you whether you value 54% (lvl 9 CS) enough more than 51% (lvl 8). By comparison, with just the Insight the merc is at 46% CS.Additionally, +2 skills from andariel's and BC should (at least that's what I've read on another forum) boost the CS to level 9 (54% chance to crit).
I think the merc is doing better against CIs even without the cham in andariel's (any reason to cham a non eth one, btw?)
Andariel's Visage Demonhead 'Cham' Defense: 313 Durability: 20 of 20 Required Strength: 102 Required Level: 83 Item Version: 1.10+ Expansion Item Level: ** Fingerprint: 0x37978aca +30 to Strength +102% Enhanced Defense Fire Resist -30% Poison Resist +70% +10% to Maximum Poison Resist 10% Life stolen per hit 20% Increased Attack Speed +2 to All Skill Levels Cannot Be Frozen 15% Chance to cast Level 15 Poison Nova when struck Level 3 Venom (20/20 Charges) Socketed (1: 1 used)
I did another 50 runs testing with a 1.07 MPK/fcr ring, and it does make running out of mana outside of mana burn much less of an issue. As in, almost forget you don't have Insight less. My runtimes weren't any better with the ring, but again, small samples and that's a lot of running for my rusty old man hands.I don't have an infinity or the runes to make it so I can't try that setup, it does look interesting if you have a FCR/preferably 07 MPK ring.