The Warp Storm

Just wondering if anyone has had much experience playing crusade for 9th edition and what they have done about setting up there army lists the rulebook say 50pl however when trying to put together an army I find it quite hard to put together a decent list below that.

https://www.goonhammer.com/the-narrativ ... sade-mode/
Goonhammer look to have best info on it.
I think the idea is to think of a theme or fluff for the force rather than being able to output a competitive force... harder said then done tho ha