Hi Sam have you used the custom window tool?
I know it is not exactly what you need yet it is a start. Can you add an image of what you want so we can make one that works for everyone?
Or you may have a window a company that you regularly specify, We can make their entire window range and have them added to PlusSpec.
Who do you normally use for your windows?
There is another way you can add your own windows, simply choose none in the window tool
you and then download from Sketchup 3d warehouse and add the window. Use the BIM tool
to add the window . TIP put the window on the window layer.
(plusSpec has just been updated so download the latest version here https://buy.plusspec.com/download