Omnotron Defense System heroic max dps

[WehrMacht]

Can you guys tell me in a few words how to make max dps as DL filler?
When i must refresh a dot and i`m channeling DL i must stop the channelling to refresh it or wait for drain life to end?

Thanks, sorry for my english:D

[Hermanni]

Switch to Shadowbolt filler, DL got nerfed.