J. Clarke writes:
On Tue, 2 Mar 2021 12:23:58 -0800, Olden wrote:


Please point me to plans for an adult senior chair.

[snip]

Take a look at the Herman Miller, Knoll, and Steelcase web sites.
You'll find very expensive exceedingly high quality chairs. If you
can afford the price, call them, give them the specs, and wait for the
truck. If you can't, once you find the chair you want, ebay is your
friend--chairs of this quality last through several owners.


I presume the OP, who asked to be pointed to "plans", plans on
building the chair, not buying it.