Hi Greg,
If you have access to a machineshop or know someone who does, I
have a simple solution to add more weight to counterbalanc your 17"
I have a 17 " on a MI-500 and was faced with the same problem.
Some "metal-cutting and welding" is what you need.
You want me to sent you some pictures ?
Regards, William Devos
e-m: wdevos42@live.com