Shower Waterproofing

I'm redoing our master bathroom. It's roughly 9'x5' with a curbless walk in shower. After raising the floor with deck mud I plan on waterproofing the shower floor with FloFX membrane which I bought from TileCoach. I was going to buy the FloFX crack isolation from the FloFX website for the rest of the floor, however they only sell it in a quantity that would give me a lot of excess.

I read I could use Ditra instead, and found I can buy it by the linear foot from Floor and Decor. Now I'm noticing a considerable height difference between the Ditra and the FloxFX. How to I make both these work for a curbless shower?

Thanks in advance@Isaac Ostrom