What are the best poultices and hoof packs for event horses and how are they used?

I am taking my pony to a 3 day event and she's never done one at this level so I want to do everything to make her comfortable. I will obviously try out any of the products before going to make sure she doesn't react negatively. I'm looking for a poultice and a hoof pack that are, most importantly, effective and, second in priority, easy to use. If you've used the product before, I'd really appreciate if you sent a link and a description of how to use it. Thanks so much!