Edit: changed the title of this to more accurately represent my question. I’m attempting to create a typeface with three different weights that don’t need to be interpolated/compatible. Image attached.
Hi, I made a mistake and set up masters even though I should have been setting up instances. Is it possible to convert masters to instances? Thanks!
Go to File → Font Info… → Exports, click the plus button located in the bottom left, and choose Add Instances for each Master.
Hi, thanks! Could you actually help me understand masters/instances a bit more? I have this typeface that varies in fidelity per-weight, so obviously my masters aren’t compatible with one another. Image attached for clarifications! Any idea how I should go about setting up my file? To include a light, medium, and bold without the need for interpolation?
OR: is having incompatible masters okay? Can you still export? 
Might give that a shot.
A good starting point is the Multiple Masters, part 1: setting up masters tutorial. It describes the difference early on in Masters vs. instances.
In your case, do as Florian suggested. Add an instance for each master. Since you have no need for interpolation, you can add the Enforce Compatibility Check custom parameter to File > Font Info > Font and turn it off by unchecking it. That detail is mentioned in the Pro Tip sidebar early on in the Multiple Masters, part 2: keeping your outlines compatible tutorial.
Hope that helps.
