the shoulders of a young pig like that won't have as much tough, established connective tissue as a "hog". As said it should be around 1hr/10lb, and there definitely is no need to remove the loins early. A fully bone-in, meaning with the baby-backs AND in-tact chine spine bone from a pig that size can easily handle over 5hrs. They get to ~145*F and stall for quite a while, and a medium-well chop is much juicier than it otherwise would be.