I would pass on the Slime Kit.
Get Safety Seal. They have better quality patches with better self-vulcanizing properties. Get yourself a kit with both patch sizes, or order the small ones separately.
You'll hear a lot of F.U.D. about plug kits. Nothing wrong with them IF properly used. Properly used means don't run the tire flat for several miles, plug it, and think everything is OK, the tire is still ruined.
Tire shops won't use them, not for effectiveness or longetivity reasons, but strictly for liability reasons. Since a tire can be repaired without taking it off of the rim, they can't prove the properly inspected the tire. A patch requires them to dismount the tire, so they can "prove" they inspected the inside of the tire.