I beleive Spike Charge for a long duration fight is the stronger of the mix.
I think it goes something like Chemical Bomb, 5x spike, detonate, restack spike and repeat as needed when dot falls off but I did not stick with sabo long to get more then shrapnel charge.
At 19 in IT I was using a similar rotation on Boss encounters. Getting a full spike charge up along with my bombs, then the blast charge. If there are physical DPS I will through in the armor reducing charges to help out some.
For pats once the tank has aggro I will use the AoE charge mixed in with chem bomb.
I dont know if that is max dps I doubt it but we cruised through I wasnt running a parse to see how it compared to the the ranger in the group but I should have lol.
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