You can always start with the tires you have and swap only if you start having a lot of issues.

One tire related data point, not just goat heads. In 2013, myself and ~50 others bicycled across Africa with TDA. Parts of Africa have a lot of thorns. On completion, we compared the number of flat tires. I had two in four months which was lower than average, though not the lowest (two people had no flats). There were at least two people who had close to *10* flats on the first day we went off-road in Sudan. Not a 100% correlation, but Marathon Plus definitely did better in that environment than the average tire.

On the other hand, I was also one of the slowest cyclists . I chalk that up more to being a slower cyclists than my tires though.