I've carried tire repair stuff since 1999. I've had an air compressor almost that long. I've got the little one that Aerostitch sells and it works pretty well. don't know how it compares with the Slime one, but this takes 10-12 minutes to air up a front from zero psi and about 15-18 for a rear. If I was doing it again, I might spring for the Cycle Pump solld by Whitehorse Press. It's a better design, even if it is more expensive ($100).
Except for a rubber valve stem failure, I've never been moving when I discovered a flat and, until Spearfish this summer, I'd never had a flat anywhere except right here in my own driveway. I'd helped other folks fix more flats than I'd had until this summer.
I've had mixed results with the Stop n Go mushroom plugs. I've had them last as long as 4,000 miles and as short a distance as about 1510 miles (the Spearfish episode during the Rally this summer). I'd fixed that one just before leaving on a Bun Burner Gold attempt. It got me to Spearfish and then went flat the next day while we were having breakfast.
The plug had apparently fallen into the tire. We tried gummy worms, but the PR3 was tough to ream out and we couldn't pull the gummy back out to seal the hole. It held air long enough to let me get to the campground and then I had to be towed to Rapid City to get a new tire.
So, I'd definitely carry more than one tire repair method, but I'd definitely have a compressor. Any of them would be better than CO2 cartridges, I think, and I can't really imagine going through everything you'd have to do use a spark plug hole as a compresson on the NT.