I've received more than one instant message claiming that my challenges are evil. So I uploaded this for you guys.
Here's a set of replays that I made a while back. In them, I defeat the Cross Wall with both Spiritia and Grolla without taking damage. Use this as a reference. Are there better ways of handling it? Yes, especially with Tia. I just wanted to give you guys a little help, considering everyone finds the Cross Wall so impossible. :3
And if you don't remember how to download things from the RKS Uploader, here's Luste again.