Yep, different mount will do the trick and scoot it up a bit. I made my own, but here's the link to Sick's web site where you'll find their mounts in two sizes, depending on your tube diameter:
You can mount it as the photo shows or turn the mount around and it will move the motor up higher in the frame from the same mount location. At least that's the way mine works and their design looks similar.
By-the-way ... did you sand down the chrome parts on your bike before painting them? If you didn't, you'll want to go back and do that and repaint. Otherwise, the paint will peel off before long.
That is a really good looking frame.