loosecannon and Jeff, I was never able to get hold of an original A/P either...even back when Bob got his two. This was when Henry had a provider with some new old Avanti stock in a warehouse, maybe in Holland a couple of years ago. I had some parts for a few A/P I took down over time but not enough good parts to build one,
I still have my original Old Top One, that I bought from Coppers. I also have a New Top One from Sirio that IMO worked just as good, as best I could tell. It was really quiet when conditions were nice...seemed like they both were.
In the pdf file below I posted what I have on file that might help with the dimensions...if someone wants to build one.
I always had great results with my Old Top One, but the hub in the ends of some of the tubing kept coming loose and it lost its match. These hubs were secured by crimping and IMO time and weather took it's tole on the parts. I preferred it a little over my Starduster because it was quieter in operations. I even put a full 1/4 wave in the top of my Old Top One and it worked out to be a little less that 90 inches" as best I can recall. I could not tell any differences. I will check my notes and if this length is wrong...I'll correct this in another post here.
I would recommend folks wanting to install an A/P do it like Bob85 has suggested. Make the mast inside the antenna 197" to 220" inches long (1/2 wave) and then put a suitable short insulator (1" to 4" inches) at the bottom that connects the support mast going to the ground. Bob used a mast diameter about 1" to 1.50" inches.
That said however, you may still have to add a choking device to the feed line to be sure and deal with any Common Mode Currents. I'm not sure how Bob85 addresses this important issue.