I have my 10 ft-er set up for car-topping if needed.
Before the accident I used lawn chairs, Nice and comfy but one day while drift fishing a small river my boat mate got snagged and I foolishly attempted to swing her back upstream to save the rig. Boat mate was not ready for that, his lawn chair tipped, he tipped, the boat tipped. (hooray for flotation foam!) Other than a loss of some gear we came out OK but lesson learned about lawn chairs.
Will not help you with height but now I use Stadium Chairs similar to these https://www.walmart.com/ip/Stansport-Folding-Stadium-Seat-with-Arms/10154040
Not the most comfortable of seats but they do provide some back support and don't weigh much more than a popcorn fart.