The 1000mm fillet limit appears to be hard coded into the plugin, however it can be easily circumvented by exporting the parameter and attaching a Constant
node. To export , right click on the generator and choose a parameter from the menu.
To align the glass edges you may need to add a segment to the corner input, otherwise the evenly calculation is not being reset for each side and runs continuously around the spline. In the attached file I've added the evenly segment to the corner slot and this seems to do the trick, but you could also add glass to the corner if you prefer.
I hope that helps, please let me know if you have further questions.