Ah yes, I did notice I had neglected to add that thickness; 4mm min thickness if from steel, 6mm if alloy.
Materials; all bar the top pair (38mm id) and bottom 6 (8.5mm id) can be anything tough, as they are wheel spacers. The others will need to be at the least steel, as they will be welded. Makes sense?

Urgent? a couple of weeks turnaround?