Hi crazydiamond,
Like mattresses, the choice of pillows are based on “needs and preferences”. The “needs” are to keep your upper spine in neutral alignment in all your sleeping positions. In your case being a side sleeper with large shoulders … a pillow would “need” to be thicker and firmer to accommodate the larger gap between your head and the mattress. The more your mattress allows your shoulders to sink in … the thinner the pillow would need to be. Because we sleep so close to a pillow though and because our face and head is much more sensitive to “feel” and our interaction with our pillow … personal preferences play a much larger role than they do with a mattress. Things like response to movement, odor, surface temperature, surface feel, scrunchiness, and other factors are a much more personal issue and even if the needs are met, individual sensitivities to different feels can play a big role in which pillow is best for each person.
For example some people may love the scrunchiness of buckwheat (it’s ability to take on different shapes) and it’s firmness or even it’s sound but others may not like it’s lack of response to movement, odor, surface feel, or the same sound that comes with changing position. The amount of buckwheat can be adjusted to meet someone’s needs but it still may not feel as comfortable as another choice for those who have other preferences.
There’s a pillow thread here which has more information and links to some good resources and pillows which may give you some ideas about the type of pillow that fits both your needs and preferences.
Phoenix