I have a couple methods of sitting.
The simplest, and despite my age (60) what I still bring on exceptionally hard (for me) backpacking trips, where I'm moving every day (AT sections, mostly), is a basic green foam pad, roughly 9x14. It rides against my back as padding, is easy to pull out to set on a log or rock during a break, and serves as a kneeling pad, fire fan, and night stand. This pad also goes on every trip because of it's low weight, low bulk, and versatility.
The next lightest is a sling chair. It weighs about 8oz, much of which is the rope. I mostly use it for hunting, dayhikes, and group camps. It's got two layers of silnylon, enabling the above sit pad to be inserted for back insulation if needed. Far easier to show a picture than explain:
The chair I most commonly use when canoe camping is the previously mentioned Crazy Creek chair, which I have to carry anyway, with my solo canoe. It weighs an unfortunate 23oz, and I'm working on figuring out a way to make one out of 2 foam pads, with duct tape for a hinge and no heavy nylon cloth cover... This chair comes in very handy in a lean-to, where you can just sit on the deacon's seat out front, or down on the shore while eating dinner, or wherever you like. It's also useful when I'm using my ground setup (vs a hammock, when it's kind of redundant except that I need it for a canoe seat), because I can open it flat, lay it end to end with my green foam sit pad) and squeeze a bit of insulation value out of it under my air mattress... this might enable me to use a lighter (18oz) summer air mattress, vs a heavier (23-24oz) winter one, on a Spring or Fall trip.
Finally, the Helinox One, that 18oz wonder... I bring it mostly on easier canoe or backpacking trips. It is wonderful, but not always worth the weight when I have the sling chair as an option.