Plan Murderhobo:
1. We take the army from Plan Surgical Strike and instead have them go planet to planet killing things.
The localised power of the strike force would wipe out everything in its pass while allowing us to keep a strong defence on our worlds. To stop the strike force, Turoq would have to devote a large amount of its forces to defence, which is practically a win for us as it means we get raided a lot less. The ships carrying the strike force need to be heavily warded so they don't know where we'll hit, but the quality/non-quantity approach means we don't need to ward that many ships.
Plan Cannae:
1. Send a large army to take a world. Turoq will send a massive force capable of destroying the army utterly to that world.
2. Win anyway.
Needs a strategic genius to pull off, but such geniuses are a dime a dozen in the Trust. One thing that we can take advantage of is how "obviously" they'll win. Turoq's generals will spend more effort messing with each other to get the kill than on actually killing us, opening up opportunities for us. Lots of other variables that can tip the balance in our favour without making it seem that way. If we win, we'll suffer significantly less raiding pressure. Disadvantage of this plan is we risk losing a large army.
Plan 'The Xenotech Heresy':
1. Steal some of the necrons' stuff.
2. Deliver it to one of Turoq's worlds.
Let the necrons do the dirty work for us. We'd need to evacuate the worlds between the necrons and Turoq, though.
Plan Probably a Bad Idea:
1. Farm orks.
2. Throw orks at Turoq.
Yeah...
Plan Nurgle:
1. Throw a bunch of Avernite plagues at Turoq's planets.
Chaos has a lot of experience dealing with plagues thanks to Nurgle, but that by no means they're immune. Chaos also has experience dealing with Tzeentch's magic and Khorne's axes - it doesn't mean they're not effective against Chaos. Obviously we're not going to use Nurgle plagues, but Avernus plagues are almost as good. It'll greatly hinder whatever Turoq is doing if we enact this strategy on a large enough scale and may give Nurgle a foothold in the civilisation, creating internal conflict. If the plan works well enough, it'll create openings for us to do other stuff.