If you're not looking to break the bank, look at Chestnut Mare Crafts on Etsy! They have amazing products and I haven't been happier with any other company :).
I think the thin ones are the best. Thin line makes a good one and the tad coffin is what I use
All half pads do different things and work differently based on the back of the horse. If you read up on what theyre supposed to do for a few you can probably narrow down 1 or 2 that would be helpful for what you are looking to fix.