Frulk, I use a two men tent:
Packed like so:
The setup is a 60 litre cargo bag sitting on an OEM rack. Over the cargo bag is thrown 50 litre Oxford Lifetime saddle bags. A tent and camp stool is strapped on the top of the cargo bag. The cargo bag has a wet weather cover over it held by a small cargo net. You can see the bag, red in colour, in the first photo. I like the cargo net as I can slip a water bottle and my wet weather gear through the cargo net webbing at the front of the bag. Makes a good back rest. In general the cargo bag holds all my camping stuff; sleeping bag, sleeping mat, inflatable pillow, spirit stove, food, EBR, cold weather jacket and hat; also spare gloves, chain lubricant and tyre pressure gauge. The saddle bags carry clothes and other personal gear that I need quick access to during the ride. The Oxford bags are top quality with self sealing zips and internal waterproof lining that can be lifted out. The whole kit and caboodle is held down by two cargo straps. I don't trust bungee cords. I have used this rig extensively and it suits me.
Cheers