...
As I strap my saddle bag to the seat post I'm using a Nitto S83 and a Brooks Swift saddle. Here's a picture
Off topic, sorry, not trying to hijack thread. I got really tired of my leg hitting my Carradice saddle bag, I put a long stem with appropriate shim between the stem and seatpost, and a short piece of cylindrical wood clamped in the stem (1 inch dowel?) to hold my saddle bag further back. Quite happy with that modification.
I also have a sheet of Coroplast in the bag to stiffen it and give it better structure so that it does not sag like a limp pillowcase.
I am also thinking LEJOG, but I would be camping with more gear on the bike than a big saddlebag.