Very good work.
You've made a lot of progress.
It's hard for me to understand some functions because I'm new to vtable.
For example.
How to get the return value
Code:
Function get_Source() As Variant
    If Left(LCase(Url), 4) <> "http" Then Url = "http://" & Url
    v = VTableCallEx("get_Source", webviewWindow, 2)
    get_Source = v
End Function