lumbersawyer, Your topic has been discussed a number of times in the past. I think you will find most everything you need with the pictures and dimensions provided in this
previous discussion of the early AD spare tire carrier. 
The dimensions aren't exact, but should give you the ballpark info you asked for.
When you do fabricate up a carrier, maybe you would take the time to document the project and share it with fellow Bolters here?
A write up with pictures, drawings and dimensions could be the makings of a great Tech Tip that would benefit many early AD Stovebolters.
