I would go with the 14 inch diffuser so you get a wider light source and I like your choice of the parchment, it would have been mine too. What color are you doing the standing part of the lamp? I prefer the black with the parchment but it all depends on what else is in the room. Love your choice.

I think you're right about the 14". Unfortunate the Wayfair site, where I plan on buying it, has a big discrepancy between the specifications and the part number,. No one there until Monday who can maybe figure it out. Some of it says it is the floor lamp and other parts of the info says it is the floor model.

i plan on getting the aluminum. I already have a lot of black pieces and one more black might push it over the edge.