Thanks for the reply. A NY winter has slowed me down a bit. Still in the same place although I think I decided to replace the old black tank (INCA Plastics) with a new Grey Tank (same INCA Plastics TANK). However I will use this as a grey tank and add a black tank above the floor. This will need to be custom. There is not a lot of room to work with.
If you are not familiar with INCA PLASTICS, check them out online. They offer up standard and custom tanks. The H4 is the one that fits the 69.
Been trying to keep a blog. Here is a link if you are interested.
https://odellryan773.wixsite.com/1969airstream
Ryan