We do a lot of apartment and deck installs. Because of strength of the railing and liability issues, we avoid clamping to railings and use a tripod.
The available tripods for a two inch actual pole are specialty items and sell for expensive prices. They are usually not carried locally by suppliers due to costs.
A subcontractor colleague of mine has solved the problem. Radio Shack stocks a heavy duty 3 foot Rohn Made in USA heavy duty tripod for $35.
A section of 2 inch actual pole is also hard to find and will not fit inside the Radioshack tripod.
A standard 1-5/8" actual galvanized chain link fence line post will fit perfectly.
My colleague developed and manufactures an adapter to bring the 1-5/8" pole to exactly two inches. The mount for the slimline fits perfectly. The clamping force of the socket's bolts transfers to the 1-5/8 pole and no additional fasteners are required.
Unlike the bucket, the tripod has a wide base and the bolts allow perfectly plumbing the pole. A few paint or Sharpie marks on the dech would allow perfect realignment; should the tripod be moved by accident.
We have done over 150 apartment installs this way. We have had no dissatisfied customers.
Anyone can buy this adapter on eBay;