Just bought the asset and I'm taking it for a test-drive to see if everything I need it to do is possible. I hit upon a bug with quad rendering - if you use a texture with a number of columns that's not equal to the number of rows, indexing is off. If you have a 16 columns x 4 rows image, the row changes once every 4 indices instead of every 16 - <quad=foo,8> draws the image at (8,2) instead of (8,0).
Traced it down to this line in STMQuadData.cs - the division should be by the number of columns (the number of images in a row), not the number of rows.
int row = (int)Mathf.Floor((float)myIconIndex / (float)rows);