Designing A Comfortable Chair

This past spring I spent a fair amount of time on our new fence.  I live on a corner residential lot and the new fence wraps around 3 sides of our lot.  We went bird crazy and cut out barn swallows in the fence panels.  Actually, let me clarify.  My wife cut out the birds!  Here is one section of the fence:

Now imagine 36 sections of fence with anywhere from 2-5 bird cut outs in each section.  I still need to finish the 6 gates but that will be an ongoing process for now.  After finishing a small project for a client it is time to get back into the shop for my next project.

I am now working on a swivel office chair for a customer.  The chair will be inspired by the Green & Green blacker house arm chair. The back splat, crest rail, and the various ebony plugs and splines will borrow from the arm chair.  The base will use swivel office chair hardware with 4 legs dovetailed into the hardware.  No arms.

A year ago I built as close a reproduction of the blacker house arm chair as I could based on various photos I acquired here and there.  I think I got pretty close:

Now, I'll be honest.  The chair is not the most comfortable chair I've sat in.  Of course, chairs in many ways are like shoes and should be custom fit for each client.  When I sit in this beautiful chair I find that the bottom part of the crest rail digs into my back somewhat.  My first reaction is perhaps I need to make the entire back sweep farther to the rear, even though the chair back already has a pretty well defined rearward sweep.  Since the customer wants the back to be like the blacker house arm chair it is important that the back be comfortable for the customer as well as look beautiful.

There is an article in issue #96 (Oct. 1992) of Fine Woodworking titled "Design a Chair that Fits like a Glove" by Glenn Gordon.  The article has a very cool chair-fitting rig.  I may build one for this project.  In the meantime, I quickly hacked together this setup (I still need to attach the swivel base):

It is not nearly as fancy as the rig in the article.  Nonetheless, I find it pretty revealing.  The shape of the splat I borrowed from my couch.  The couch is a new Scandinavian style couch with great back support and curvature.  I took some 12 gauge electrical wire and shaped it to the shape of the back of the couch.  I then used the wire to quickly draw the curve on some 8/4 lumber.  It is a very good starting point.  I can move the  entire back forward or rearwards as well.

For the crest rail I've tried 2 orientations.  The first orientation is where the crest rail sweeps back following the curvature of the splat, similar to the blacker house arm chair:

The splat has nice lumbar support.  However, the bottom of the plywood crest rail sticks out which is very noticeable when sitting.   I tried moving the entire back forwards and backwards and I still experience the bottom of the crest rail digging into my back a bit.  Next I straightened the crest rail so it is more vertical and in line with the back of the splat rather than the front:

With this scenerio my back rests upon the entire crest rail rather than the very bottom of the crest rail - which I find more comfortable.  What kind of design follows from this?  Here is an absolutely beautiful chair designed and built by master craftsman Jeff Miller where the back of the chair sweeps forward at the top rather than rearwards as with the blacker house arm chair:

So I will explore the forward sweep in the context of the Green & Green design motif.