I'm sure a lot of people already know that it's an issue to find a free spot at Cave Horrors without there being 7 people located within the entire cave taking the spawns.
I've explored the eastern part of the cave and noticed that there are absolutely no NPC's there whatsoever (see image below)
(There is way more of the area than what I screenshotted)
What I suggest is filling this entire vacant area with around 5-10 bats and 10-15 Cave Horrors.
This way it helps other players complete their slayer tasks more efficiently and provides more people the ability to kill them.