Phew! So much to consider! Thanks all for helping out with your posts. What is good to know is that this is not a unique problem to me, or there wouldn't be arm rests, etc. on the market. Feels better not to be alone
Let me start with Brian's comments. Brian says that one must be careful to not apply too much pressure with the arm. Mrs. Segovia said the same, i.e. that I seem to put the whole weight of the arm on the guitar. This is true, I do let the arm rest fully against the guitar. I find that if I keep it lifted I tense up, especially my right shoulder and back. I am really trying to minimize tension, and maybe I am taking it too far? Is it the common practice to not let it rest fully against the guitar?
The other point Brian makes is that I could try making contact further up the arm, on the meatier part below the elbow. I have tried several ways of doing this, and not always specifically because of this problem. This is what I've tried and the results I've had:
1) I keep the guitar positioned as it is now (i.e. as the pictures above show) but simply move my arm down a bit. Problem I have with this is that I then need to bend the wrist in order to have a "home base" of ima on 3-2-1, which is a no-no according to my teacher (I know what your thinking, please see the end of the post
2) Again, keep position as is now but move my arm more towards the end of the guitar, past the bridge. This gives me a contact point in a more comfortable place on the arm and I don't need to bend the wrist. Two problems though: I need to slouch in order to get the arm there and my thumb both looses its freedom of movement (because of the angle between the arm and strings) and the thumb's natural resting place is above the 6th string.
3) In order to minimize the slouching problem from point 2 above, I can angle the neck down, to be more parallel to the floor. Problem is of course that now my left arm is uncomfortable, and fingering becomes more difficult. For instance, keeping the palm parallel to the strings (or fingers perpendicular to the strings) necessitates quite the sideways bend of the wrist. I find the neck angle I have now to be very comfortable.
4) Have my lower arm surgically shortened. Problem: it would look funny I think
On Brian's question as to whether I pluck from beneath, I just checked and I don't think I do. It takes a while for me to get in position, and with the camera on a tripod and timer release I don't have time to get in the exact
position. It looks like I do from the picture, but I try to press the string down diagonally towards the soundboard before releasing. I'd like to have my fingers straighter/taller, but I run into the bent wrist problem.
Seeing the Oasis sleeve and home made rest has given me some ideas. I just tried with the sock and some rather thick leather (from a long sleeved gardening glove) and it was a huge difference! I will continue to experiment with this as well.
Intune, I checked out the Plenosom rest. It seems designed to go over the wrong part of the bout. But I am going to call my luthier (Antonio Aparicio) and see if he's got something.
And yes, I do have a teacher. Why don't I just talk to him? Well I have and he's had a suggestions. The option 1 above. His solution to the bent wrist is that I should push my elbow forward. But I can't keep it that way without conscious effort and some tension. As soon as I stop concentrating on keeping the elbow forward it goes back to its natural resting place and there goes the bent wrist again. So, I'm looking for more advice.
Thanks again, and sorry for the super long post!