Bit off topic but I did wonder how well a Camper Longflap would sit across the top of panniers. I’m suspecting that the saddle loops would not be secure enough and that additional straps would be necessary.
I tried that a long time ago, and used bungee cords to secure it. But in that configuration the only advantage I could see from using a Carradice saddlebag was the relatively good waterproofing. A waterproof Ortlieb bag works just as well and can carry more stuff. Or a (not too huge) regular rucksack, which is more useful if doing fixed-centre touring with some walking involved.
Most of the time I use a saddlebag in either/or mode with respect to panniers. Saddlebag if the load will fit in it, reasonably fast removal is then a requirement, as in the rare cases where I leave the bike locked up somewhere I then take ALL the luggage except water bottles (i.e. one saddlebag) with me. If I need more space, in order of volume:
- a pair of medium rear panniers,
- medium rear panniers plus front panniers OR large rear panniers without anything else,
- medium rear panniers plus front panniers plus luggage strapped onto the rear rack OR large rear panniers plus front panniers,
- large rear panniers plus front panniers plus luggage strapped onto the rear rack,
- large rear panniers plus medium rear panniers carried on the front rack plus luggage strapped onto the rear rack.
I have only ever needed the last configuration for local utility trips. And for exceptional loads, depending on the weight, size and awkwardness of the load I also have the additional option of a large two-wheel trailer, which has carried maximum loads of 500 litres or 130 kg (not at the same time)