Perhaps a pad with shims. It's very important to be sure that there aren't any "edges" where something that is used to lift the front end suddenly stops... it needs to taper as much as it can. Thinline pads are known for helping to distribute pressure points more evenly, so I would suggest looking into these before you add too many correcting pads. Unfortunately the best options also tend to be the most pricey.
Here's something you might consider looking at: Dover Saddlery | Mattes Quilt Correction Half Pad .
In this case since you need a bit more lift in the front, you would be removing the shims in the back half of the pad and keeping the ones in front.
If I were in your position, I would put my pads on in the following order:
1. Basic quilted pad (such as the red one in your pictures)
2. Thinline half pad like so: Dover Saddlery | Ultra Thinline Half Pad .
3. Correctional pad with shims in front (such as the one I linked earlier in the post)
Not cheap... but it's my idea of what would be the most effective while preserving your horse's comfort.