Just a side note: The Sunn tolex is unobtainium to my knowledge. Over 6 years ago I actually purchased some Sunn tolex (Fender era reproduction) from Conrad Sundholm. I think Conrad had access to purchase this tolex from Fender at that time. I built a missing amp back panel for a late 60's Sunn 1200S and the tolex was a virtual match to the existing amp tolex. And, no I'm not selling any reproduction tolex, sorry! I'm saving it for future restorations.
Also, if you are in need of Sunn corners, Reliable Hardware carries both the 2-screw corners, 3-screw corners and correct #6 X 1/2" truss-head screws. These are an exact match for the original Sunn corners. I've used these on several 60's era Sunn amps. No affiliation, just trying to help my fellow Sunn collectors!