Thank you for your suggestions.
I've just come in from planting all the iris. What a relief to have them finished for now.
The place where the sibs went is a built up hill and it's sandy so I planted them where I want them to stay. For the TB I put them in a free spot in my raised daylily beds and will leave them there until next summer. They're close together but since they won't be there long I think they'll be OK. In the mean time, I'm researching tillers and plan to get one and till up the clay bed before putting the TB in it. That bed is next to a section of the yard that has lots of trees and lots of leaf fall. I'll be tilling in a bunch of leaves and their wonderful leaf mold to amend the bed.