you may already have the info you need, but i just returned from a 4 day/3 night lower zambezi river canoe safari operated by river horse safaris. the guide, martin, was excellent. it was "participatory" camping style, which was fine by me. i was traveling solo, but the group with which i connected had one other single traveler so we canoed together.
the game viewing was not hugely diverse, but it was beautiful. we saw tons of hippos, crocs and elephants. we also saw impala, warthogs and a wide variety of birds. I enjoyed seeing the animals from the water's level, but if you want to stop and gaze, this probably isn't the trip for you. The current moves you and you do have to manoever around hippos and in-water stumps/trees, so there is not a lot of lingering time when you are in the boat. of course, when you get out of the boat, you have time to linger all you want.
the food and campsites were absolutely lovely and simple. the tents and sleeping linens/bags were perfectly adequate.
i enjoyed my trip. i was happy with the 3 night option (plenty for me; i'm not a water rat) and highly recommend Martin, who was a wonderful guide and kept us safe and happy.
i also stayed at Zambezi Breezers outside of Chirundu, Zambia for the night before the canoe trip started, and that was a great choice. the trip leaves from Breezers (i.e. Zambia), so it's convenient and a beautiful spot.
Hope this helps. Feel free to contact me with questions.