Nice write-up and photo-documentation on the BBW conversion. I am going to try the 3M, #8115, Panel Bonding Adhesive. It would make the conversion a lot less labor intensive, with regards to welding, grinding & top-dressing all puddle welds around the perimeter.
A completely restored factory dash cluster with gauges is less than $400.00...including night-glow green on inside of case, zinc-coat on outside of case, non-glare black on face of gauge backing plate, alumi-blast & clear on bezel surround, vinyl gauge faces, polished lens, refinished needles, bench-tested gauges, speedo lub & reset and new lamps. We have done several of them and they look amazing when they are done properly.
You can also purchase them refurbished at:
www.bowtiebits.com