The glasses in my virtual try-on sit too high and look too big. How do I fix the fit?

Adjust the Placement values for that product. Go to Plugins → Virtual Try-On, open the Products tab and click Edit on the product. Under Placement:

• Scale: size of the image. 1.0 is the detected face width, so try 0.9 to shrink it.
• Offset X: moves it left or right, as a fraction of the face width.
• Offset Y: moves it up or down, as a fraction of the face height.
• Rotation (°): tilts it in degrees.

Make small changes, click Update try-on, and test on the product page. A tightly cropped, front-facing transparent PNG also helps it line up.