Foam thickness on a teak armchair (ID)  

That seat looks a little low in relation to the arm height so you may want to do a 4" thick cushion on the seat and 3" on the back. Most chairs look good with 3" and 2" but some need more.
Once you add in the thickness of the upholstery batting that is glued to the foam, it will be a little thicker than 4" but not a lot. The batting is essential. Just don't over do it---you don't want the poufy overstuffed look of traditional furniture. One layer of 1/2" or 3/4" on all sides except the back end is fine.
You should also go one level firmer on the seat than on the back. If you use the same firmness (density), the back will feel too hard.

Thank you spanky

Hi vintagestique
just wondering if you ever identified the designer of this chair?
Was it walnut?
thank you,
L