Jamón is rear leg and Paleta is front or shoulder leg. The size is the main difference. Our Jamón is 16lb average and the Paleta is 10lb average. Both taste very similar. The paleta has more bone and complicates the carving a little bit.
Jamón (rear leg) 16lb yields around 45 to 50 plates (2.5oz/each).
Paleta (front leg) 10lb yields around 30 to 35 plates (2.5oz/each).