I'm biased. I despise drop holsters. The only reason to use one is to get your handgun below body armor and battle rattle. When fully kitted out, I would use a "jacket drop" for my duty holster. As long as I had a hood on the holster to protect the holster retention from the bottom of my vest , I was good.
You MIGHT find a modular system that accepts a kydex shell for a Shield, but I doubt you'll find a decent drop holster appropriate for that pistol.
Do you know if there is any logic behind requiring a drop holster? Will you be taking the course in tactical gear (body armor, duty belt, etc)? Is the instructor someone you have a dialogue with, and you could ask?