Slime is different than Fixaflat . I wouldn't put Fixaflat into a wheelbarrow tire. Slime on the other hand, is a great product. I put it in my ATV's as more of a preventative than anything else. Since I've started using it I have had 1 nail puncture that sealed up immediately. It let me finish my hunt. I have no doubt it would get you to the repair shop much better than Fixaflat.
Unfortunately, nothing works on a sidewall rip except a spare.....
Regards, Vince