Respecting number of posts per page

Hi there, great plugin, the sticky-ness is working well for me.

But, it’s not respecting the number of posts per page. I have my custom post type to display 12 posts, but if I make 5 posts sticky, I then have 17 posts in the first page which isn’t ideal.

I’ve tried setting the number in settings—>Reading, and also in functions.php using pre_get_posts. Is there any way for it to display the 5 sticky posts, then the next 10 on the first page, then the next 15 etc…

(Keeping in mind the number of sticky posts may change.)

Thanks,
Dean.