Umm... Mine were... Hmm. They were either lower control arm bushes or leaf spring bushes, I don't really know. Else, I've seen people use even garden hose or anything else that fits.
When you install them, set them about the correct height and put a dab of oil or grease on the tip, and close the bonnet. Then you'll have a little spot on the bonnet where you need to drill. From there, Have Fun. Drill a hole, close bonnet, see where it's fouling, drill more. Lots of fun. NOT.
If you don't want to drill holes in bonnet, you can always make a secondary bonnet restraint out of chain, link, leather belt, whatever really.