Okay...after 5 hours of wrestling with this machine, I put Cap's mods in the back (diverter mod and posts) and...
I still can't get a clean left orbit. The ball still gets hung up under the left gate, too, but I think if I just loosen the screws on the back panel and lift it up a bit, I can keep that from happening without ripping it all apart again.
Cap...your diverter mod never actually sat flush with the diverter arm no matter what I did, and I think that is the reason my orbit shots still aren't clean. I loosened the diverter and tried to adjust it forward (couldn't), and finally ended up pasting the diverter mod to the ball guide with mylar to try to press it as flat as possible...but I guess it still wasn't good enough.
I never had a problem with throne bounce-outs and still don't. I have your C-shaped thingy, but I'm not sure if I need it, nor am I sure exactly how it's installed since nobody has posted a throne picture with one in it.
So, I'm a little depressed about it. But you CAN finish Martell without left orbit shots, but that's bullshit that it was designed so poorly. Hopefully there will be another solution and I can waste another 5 hours of my life doing something I paid to have somebody else do.
On the bright side, my ramp doesn't launch airballs anymore...