Crazy creek chairs are great. The newer ones that are designated as "canoe" models are handy because they have straps w/quick release buckles that wrap around the bottom of the canoe seat so they stay put and are easy to get in/out. They also have quick release buckles on the straps that go to the chair back so you can quickly un-clip the back and have full range of motion when you really want to dig in paddling.
Sitting in a crazy creek around camp is very comfy for me. Some people don't like them though. It can take a bit of adjustment on the side straps to get the chair to feel right, but it's pretty easy to do. If you don't like sitting on the ground at all, I'd say definitely try before you buy.
I have the Sitbacker and find it to be more roomy/comfortable with better back support than my Crazy Creek. Unfortunately it is 16.5 inches wide and will not fit back far enough on my stern seat without the frame rubbing on the gunwale. So it's Sitbacker on the bow and Crazy Creek in the stern for me.
Sitbacker for me. I had a crazy creek style canoe seat through last season and the quick release buckles gave way by the fourth or fifth day out. No problems with the sitbacker.
I bring my Crazy Creek for use in the canoe and in camp. I like to use it while I cook meals on a log sitting around the fire or on a rock with my stove. I older I get the harder the rocks get.
There are other brands I am sure would work.
Sorry I read your post wrong--I was thinking you had a support for your canoe already. Here is what I use---
canoe seat