Hi Chris - take a look at this link in the archive section of Airstream.net.
www.vintageairstream.com/archives1/59Tradewind/59TW.html
This is my TradeWind and it didn't have either tank in it when I got it. I
put in one under the commode and use a blue stinkie for the grey water. I
know, its a pain but I didn't want to tackle having one made that fits
between the frame rails. The stinkie works for now. I like the idea of
pumping it into a tank in the truck bed. have to give that some thought.
Good luck and enjoy your '59 Trade Wind. Let us know when you get pictures
uploaded. I'd love to see them. What is your serial number?
Brad Norgaard
Phoenix
'59 Trade Wind Twin
VAC #2699, TCT