I can’t imagine it would make much of a difference. As I understand it the hulls are there simply to provide structure to the mash so it does not stick on runoff.
I don’t know man, I had a hellacious stuck runoff on Friday with my oatmeal stout. I even conditioned my grain. Maybe because I milled at .032" gap. Either way, the crush looked good with husks in tact. But got a stuck runoff even when running off slowly. So I stirred in a few hands full of rice hulls and it helped tremendously.
When I look at my grain after it’s crushed, I see hulls (some whole, but split open) and bits of endosperm. I can’t imagine why I would need more hulls. If you’re shredding your hulls, then maybe it’s time to look at your grain mill/gap/speed, etc…
I havn’t personally used rice hulls or oat hulls but I think the idea is that if you have a large amount of grains in your grist that do not have or have very little hull then the rice/oat hulls balance out the proportions. That being said, the last time I made a hefeweizen I did not use rice hulls and the 60% what malt did not cause a stuck sparge.
I’ve rice hulls once. I can’t imagine that it makes any difference what kind of hulls you use. If you do your sparge right you won’t get much out of the hulls themselves anyway. They are just the filter.