I actually have had quite an evolution concerning the use of shoulder pads. I will say right off, that this is a very personal decision and I believe there is no set formula concerning whether one should use one or not.
When I first was became a student of Karen Tuttle back at Peabody in 1984, one of her first tasks was to “balance” me with my instrument. This involved cuddling the viola between the chinrest under the jaw bone and the shoulder against the shoulder pad. The shoulder pad could then be customized by adjusting the height and tweaking the fit with small sponges. The purpose was to have the instrument so that one’s left hand could be totally free and relaxed with an energetic, plopping finger action. This worked wonderfully for many years. In fact, I also have replicated this for others in order to relieve people with tension in their necks and/or left hand.
When I studied with Joseph De Pasquale, one of his first requests was that I remove the shoulder pad all together. He did not use one as his teacher, William Primrose, did not. They insisted that the shoulder pad constricted too much sound of the viola. This was always uncomfortable for me since I always felt the viola was unstable and sliding around. This would lead to tensing up my neck and gripping with my left hand. Playing without a pad was something I would quickly abandon.
Only about three years ago, I attended one of the many classes that Kim Kashkashian gives at the Curtis Institute. She for many years has used just a small cosmetic sponge held in place with a rubber band. At this particular class there happen to be not enough seating, so I sat behind Kim and watched the class from behind. This turned out to be a day of great revelation for me. I realized something that had eluded me previously when Joe had me go shoulder padless. Watching Kim from behind taught me that without a shoulder pad one could stabilize the viola without holding it in one place. Her shoulder was assisted by the small sponge for traction.
By not keeping the viola in one set place, she was able to vary so much better the angles of her bow, sounding point, and overall colors in her playing. Surrendering oneself to the flexibility of movement was the key. I had previously been fighting to keep the instrument in one place with the molded pad.
This has been a real journey for me and contines to be so. Currently I use a small rubber rectangle made by "Acoustifoam" by Tamsen Beseke. It is light and gives me the traction I need. I do not use the standard type shoulder pads anymore. Does this mean I will never go back? I don’t know. I will just keep experimenting and encourage all to do the same.