I rummaged around till I found this motley collection of parts
The dowels aren't the same length,
which worked in my favor
since the bottom PVC T on the jig
was deflected by the Galvanized T
on the loom itself.
If the dowel had been longer
the jig wouldn't have fit.
that hold everything in place.
(Broccoli comes with the nicest rubber bands).
You also might notice
that the top dowel has a cardboard shim--
an easy way to make slight height adjustments.
filled with supplementary warp:
fly Line Backing in white,
for the top.
once everything is secure.