Changing Spin Button and Adjustment

[Brian Clark <bc viz tamu edu>]

I have an adjustment for a spin button, and I want to change the upper 
value of the spinner (and therefore adjustment) after the window has 
already been created.

Is there a way to change it directly?  Or do I have to create a new 
adjustment and assign it to my spin button?
And if I must create a new one, what's the proper way to dispose of the 
old one?

Thanks,
Brian