Ball cover and design is only one of a number of factors in ball spin. Angle of attack, quality of contact, etc., if ideal you can spin a Surlyn cover ball. Ball design and material is a factor so you have a better opportunity to spin a ball with the soft cover.
I generally play a Surlyn ball in the winter and when the greens are soft. But, as we move into the summer with firm, quick greens urethane is what I use. It is difficult for me to achieve predictable spin with the Surlyn ball. When everything is right it will spin and stop. Urethane provides a material when you have a less than ideal swing to stop the ball it will still slow enough to stay on a firm, quick green.
The ball flight is also important to spin so the number of dimples is a factor. Higher flight with some ball design will shorten distance on average. But, urethane is really not a factor if you swing up on the drive and reduce ball spin in flight. The whole concept of a urethane cover is you compress it enough to reach the core material and negate the cover. If you put a lot of spin on the ball with your driver, swing down or even level with a higher lofted driver, you will definitely lose distance with a urethane cover. Swing speed is also an issue. You have to compress the cover with a urethane cover to make it work ideally. The urethane can be customized in thickness or the material to fit a players swing. A urethane ball can be designed for a slower or faster swing speed. However, it is most effective for a high swing speed.
Did you know a number of players on the PGA tour will play a surlyn cover when it is ideal to bump and run? The British Open was well known in the past for players to use the Top Flite rock to negate spin and be consistent with their bump and run game.
It is helpful to find what works for you. It may not make a major difference, but a stroke here and there can make the difference in who buys on the 19th hole. 🙂