Step 3: Assembled
The rubber foam is very cheap-less than $5 for 6 feet. It has two self adhesive strips on both sides of the slit. It is very sicky so care is needed when doing the final fit. I used PVC cement on the top elbow joints-didn't want to risk it popping apart and dropping the guitars. I measured for 6 inches between the teeth for the archtops and 4 inches for the other two slots.
One improvement you should consider is adding a cross support halfway up the back. The unit is fairly sturdy now but does have a little sideways looseness.
Whitman still can't figure out if this is food, a toy, or what...