This should help with the rear attachment.
I attached 1 inch pipe to the back of the seat braces and to the side of the rack. You can see the 1/2" pipe going into the 1" pipe on the right hand side. That 1/2" pipe goes the entire inside length of the 1" pipe and butts up against the T attached to the rear fo the seat(I think it helps with stability). The two lower pieces of the 1/2" pvc slide into the lower frame mounts near the middle of the trike. They can be seen in the split side view photo.
The other shell you see is hopefully going to be a streamliner for Battle Mountain later this year.
JJ