I have different weight values for my Masters, but I cannot export my instances. Would you please help me to fix this?
Your desing space is not properly defined. Meaning: You have not got masters at the extremes of both your axes. For two axes (let’s say, wght 100–900 and opsz 1–10), you need masters at 100,1, 900,1, 100,10 and 900,10.
In design terms, this means that you need to design Regular for small optical sizes, a Black for small sizes, a Regular for big sizes and a Black for big sizes.
I hope this makes sense. In the specific case above, you need to set opsz to the same value in your Regular and Black master, then set the wght value in the Regular Display to the same value as in Regular (100), and then add another master Black Display with the same opsz value as the Regular Display and the same wght value as your Black (200).