Ive seen recommendations that the l98 valve spring seats/locators (pn 10185066) are better for the crane 99893 springs than the crane shims/spacers, because the locators hold the spring and prevent "spring walk".

I dont see how they do this. The shim is a disc with a hole in it, and the seat is a disc with a hole in it with a raised border around the hole.

 

24hr ttt, actually, its more than that

 

Locators do just that, they locate the spring to keep it from moving around.
Shims just take up space to adjust the installed height. You need to be sure
that the ID of the spring in question is slightly more than the OD on the seat
(locator). Also be sure to check the ID on the inner spring if it's a dual spring.

 

You can get spring cup's ie. locators in different thicknesses,so if you need shims too you may be able to cover it with just a cup.You need cups to keep the springs centered over the guide,especially with larger dia. springs.