Just like when buying our machines ... go to the store and test drive the possible chairs!
Adjustable typewriter or drafting chairs are usually good for sewing.
(the drafting lowest setting is the highest of the typewriter)
I got my last one at Staples, and took it home, with the full agreement it could be returned if it just was not "right".
Another consideration ... how wide is the chair and the base ... will it slide into the hole of your sewing desk/table when you are not using it.