I have the normal spare wheel and carry a spare tyre only on the roof. I store a few things inside it. Over the last 4.5 years and 157,000km I have destroyed 2 tyres completely! I have also repaired several punctures. The tyres are available in South Africa but not in the Americas, but you can order them; 3 to 4 month shipping time.

With the split rim wheel they are easy to change, see my video below. I actually do it with the wheel still on the axle these days! I also recommend you use balancing beads.

Hope this helps

https://youtu.be/GkBFpRuLlAI