Spinskins just disentegrate after awhile. I never got 1000-3000 miles (as they claim). No way maybe 500. They just come apart in pieces. Maybe they don't like Slime.
Too narrow also. Assumes stuff ain't going to come in the side. Maybe the Duros last better.
The normal tuffy together with Slime is enough (especially now that i learned what to do with the ends). Nothing will stop all real thorns except thickness+Kevlar IMHO, then slime for that occasional one coming through.
I would rather have the kevlar built in the tyre, like Specializied's Armadillo, a tuffy, and slime. This is for serious thorn country off road.