heya fellow warp entities,

I have a question I want to ask thee^,^

I want to convert a tyranid ravener into a fiend of slaanesh, because I hate those models.
But I want it to look like a daemon, not a strange tyranid.
So, I'll take a gene stealer head with feeder tendrils, flesh hooks and acid maw, and convert it so it will look less like a gene stealer.

I will give it two scything talons, converted to look like the daemonette ones, and two rending claws(just cause there cool).

But, what about the body? and the back? tyranid bodies are huge, and just closing the external ribs with green stuff will make it look like a toad.
but if I remove them, then what do I do with the space?

and, I wanted to make a fin, like the mound of the herald in fantasy (warriors of chaos).
but how do I make that?

any tips?