I wouldn't consider the SPOT for myself. I'd either get a true PLB (like the FastFind) or the InReach. Both have global coverage. One is subscription-free and works with COSPAS/SARSAT, the other has text messaging and works with Iridium.

Recoil on the .454 Casul is stout but manageable for many folks. I'd be more inclined to go with something that had more capacity and was easier to practice with. A full-size striker-fired .45 might work well.