Careful with your approach. Schluter does not endorse the use of any liquid waterproofing with their product. I'm pretty sure if you go this route you will have zero warranty from Schluter.
Perhaps call Schluter and ask;
Contact Schluter Systems USA
Schluter Systems L.P. (USA)
194 Pleasant Ridge Road
Plattsburgh, NY 12901-5841
Contact Schluter Systems Canada
Schluter Systems (Canada) Inc.
21100 chemin Ste-Marie
Ste-Anne-de-Bellevue, QC H9X 3Y8
You could consider using a linear drain from Quick Drain USA and then using Hydro Ban from Laticrete. This has been tested by Laticrete and this system is approved by Quick Drain.
Many of the other linear drain suppliers work with a standard three piece clamping drain.
The drains from ACO, My Shower Grate Shop, Infinity and CeraLine can all be installed with this type of rough in and a liquid membrane. I prefer using Noble Seal TS for my clamping drain installs and have been guilty of using a liquid on the walls. I've spoken with Eric at Noble and he tells me that they have done plenty of projects with Laticrete and Mapei, but Eric did not come straight out and say that the warranty is still OK.
Your safest approach is to stick with one supplier like Laticrete or Mapei and take the job start to finish with their products.