I love that plant, nice choice!

I'd say it's a front/mid-front of the border plant. The foliage is about a foot tall and it's nice looking - or at least it's not offensive in any way. Spacing is maybe 16" or so. A foot seems too close, so something in the 16-18 inch range feels about right. Mine have filled in around the original plants with seedlings so I can't say what the spacing originally was.

Full sun up to about half day shade is what they get here. The long stems are fantastic. They are a mainstay in bouquets and they go with just about any color.

I hope they prove to be good plants for you. I just love mine and have them in several places - they seem happy everywhere!