Sytas Office Chair Ergonomic Desk Chair, Rolling Swivel Mesh Computer Task Chair with Flip-up Arms Lumbar Support and Height Adjustable, White

I need one that can go up 20 inches. Will this chair accomdate that?

During move out I lost the four screw for the cushion where I can buy for it ? And which size

is anybody able to share the instruction manual with me? It is missing from the box. I've already had to send this chair back once bc part was missing

What are the dimensions from arm to arm, and diagonally across the wheels?