Tzeentch likes knowledge and Sorcery.
So, what I figure we should do, is RIP AND TEAR our way into, say, an Imperial Prison, find any heretical confiscated materials, and release it to the public, to help get the people sympathetic to our cause.
We RIP AND TEAR, so Khorne is pleased.
We JUST AS PLANNED and HERETICAL KNOWLEDGE so Tzeentch is pleased.
And perhaps rape/torture a few prisoners for Slaanesh.