Drum Shades

I'm thinking of adapting the current dining room light to accept a drum shade. I'm wondering it is as easy as I think it may be. Probably not!  I would take off the black disks and attach a drum shade to cover most of the lights. How to do this is the mystery.

Here's what I would love to end up with.  This is the Jonathan Adler Ventana chandy.

These awesome shades from Shades of Light would all be delightful. Though, I really think a 20" diameter shade would be ideal and those are harder to come by. These are all 16" diameter:

Aren't they pretty? All are under $100 which is pricey but cheaper than new light fixture.  I will think about this and decide what to do.  It may be easier to replace the whole darn thing.