Check out the Tech Tips on Wheels and Tires at Wheels and Tires - Tech Tips scroll down to the discussion under 1.5 & 2-tons to: (Note on the 10-lug wheels with 7.25” bolt circle) where it Grigg talks about clamp plates. There are links to pictures as well. May not solve your spacing issue but may solve the "Where did these come from?" questions.

Roger

Roger Burgoyne Member # 42,919
1948 Chevrolet 1-1/2 Ton Loadmaster w/Dump
Terre de Bourgogne Llama Ranch, Arizona