Shaped pad over a square pad used to be "in style" when I rode H/J back in the 90s in Southern California. Most girls would be riding in that combo in lessons or at schooling shows.
You want to make sure that your saddle is wide enough to accommodate all that padding. If the saddle "just fits" without any pad or with the quilted pad, then adding extra will actually make your horse less comfortable. Think about when you put on too thick of socks in dress shoes or cowboy boots. It's fine for a while, but then your feet begin to cramp up.
If you want something shock absorbing and cushioning that won't change your saddle fit, I'd HIGHLY recommend a ThinLine Half pad
or Contour Pad
. They do a great job of absorbing shock and reducing "bounce," making gaits a bit easier to sit. I really like the results of my ThinLine pad. And they have a guarantee, so if you don't love it, you can send it back for a refund of the purchase price (less shipping).
If your saddle is wide enough and you want to use a Sheepskin pad, I'd go with an Engel pad
. They are very high quality without being so expensive. My daughter has one and it's held up well through many washings.