The core is of a more slick material, and more flexible alone, so if you use that, it won't rub through the spin as easily.

OR...if instead you remove the core and use the cover, now the cover is much more flexible, and can flatten out going over the hoop, so then it won't rub through as much either.

And yes, you want as thin a line as will work, remember, you have still to clete it.