Overall, I'm really happy with these new WebFMCs, they really work much better than I would have expected and have a lot of potential uses. Thanks!
For the P180, this change to the config.js fixed the clipping at the bottom and right and gets the text aligned correctly with the buttons for me:
const screenXY = "left:25px; top:62px;";
const screenWidthHeight = "width:660px; height:440px;";
Also, for the P180, the buttons in the index.html had white outlines, those should be made transparent like the others.
For the AS530, this worked for me to fit the window correctly:
const screenXY = "left:129px; top:47px;";
const screenWidthHeight = "width:538px; height:404px;";