If I had the skill-set to make one of these sights, I think I'd start with the front globe assembly, probably the dovetailed unit...the way I'm seeing this, that front globe assy. will determine your line of sight over the bore. The rear can be made to fit...me thinks?
EDIT: I was looking back in this thread and discovered some pictures you posted (page 4, post number 74) of rear sight assembly's you found for sale...
¿- Can you purchase one of these yourself? - Can you get them shipped by the seller? - This would save you lots of time & the frustration of a DIY build.
(If this is possible, I can send you the funds to cover this rear sight also...let me know, OK?
The front globe assembly, I can purchase and have sent directly to me...then ship to you without any markings to indicate 'gun-parts'.)
"Just a couple of thoughts to get your build up and running!"
OOOP's Second EDIT: Further review of this thread showed me that you already have the rear assembly and the work you are doing is to fit a bar, a dovetailed length bar to the receiver..."Sorry...I have a very short & blurred memory! Never-mind my blundering!"