PAXboy
Interesting pair of questions. A complete answer to your first one could fill a small book while the second is a lot easier.
So Q2 first. On conversion, by the time you are half way round your first circuit you will probably no longer notice whatever control yoke your hands are using (unless it has been badly designed - which is unlikely unless the aircraft type goes back say 40 years or more).All you will be conscious of will be the forces and displacements you are using and whether they allow you to control the attitude of the aircraft to your satisfaction. Such matters tend not to be determined by the shape of the thing you are holding.
That probably gives you a clue about the answer to Q1. The primary purpose of the yoke is to allow you to apply forces and displacements. In pre power steering days much muscle could be needed to deflect controls into the airflow. Hence the leverage that could be applied was important in sizing the yoke so far as the ailerons were concerned. For the elevators it was necessary to put the yoke on top of a suitably long column to get the fore and aft leverage to make the push and pull part of the job doable. Where the yoke was mounted on a rod that came and went in and out of the panel (as it were) then there was a lever somewhere below in the works which had the same effect, it was just kept away from your legs. Power controls sorted out the leverage issues of course.
Then there is the need for the necessary movements to be possible without the yoke getting too close to you chest or thighs. Not that easy when considering the large size range of pilots. Toss in the need for pilots to be able to move themselves up and down to see out properly and the things can be quite a problem to resolve to everyone’s satisfaction.
All this can be made harder if the cockpit is on the small side. Here, the rams horn shape that you mentioned in Concorde can be a help in missing your thighs when full aileron control is applied, especially if a lot of rudder is also needed for asymmetric reasons. The leg you push with tends to go down and out of the way as it gets straighter, but the other foot moves towards you, that knee tends to stick up and foul the aileron inputs (even foul the elevator inputs in the DC3 for example – a poor design case so far as this topic is concerned but it was done 70 years ago)
The Trident also had a Concorde like yoke. Both aircraft benefited from less yoke inflicted obstruction of the pilots view of the instrument panel. Having to peer over and round the yoke to see and reach something can be a right pain.
I will stop there as I am sure you get the drift that there are a bunch of things that drive yoke design.
Regards
JF