I would like thank everyone that provided input based on their personal experience with the panniers that I was considering buying. It was very helpful.
I decided to order the Carradry panniers. They arrived yesterday. I think they will be exactly what I need.
I changed my mind several times on which panniers to get. At times I was leaning towards Altura. And at other times the Carradry. And the Altura ones, I went back and forth on which model. I could not find a retailer that had the Super C at a good price with shipping to USA, so the Super C fell off my list pretty early.
To clarify some of my needs, I already have Ortieb Backrollers but I am looking for larger volume panniers for one or two specific trips where I would not be using front panniers. I expect to use my Backrollers for most tours, I do not anticipate a huge amount of use with these new ones. Thus, I was more focused on low cost and the cost of shipping, not long term durability. Rack attachment points are important too, but it was less critical than cost since they are from reputable firms that are unlikely to sell anything bad.
The best price in US Dollars with shipping and without VAT that I could find for each are as follows:
- Carradry $100.26
- Altura Dryline 56L $103.68
- Altura Orkney 56L $129.60
- Super C with one tin of wax $197.39
The day I ordered them, I actually changed my mind twice during the couple hours before I ordered them. One reason that I ordered the Carradry is that I found two YouTube videos that described them and I could see how the panniers attached to the rack. The Altura ones, I could not find any good photos or other sources that showed how they attach to the racks. Now for the funny part - when the Carradry ones arrived, that is when I learned that Carradice have modified their rack attachment system again, thus I got something slightly different than I expected. But, they look like they will be perfect for my needs, so this surprise was not unpleasant.
Thank you again to everyone that provided input.