The first line of defense against flats is the tire, I think we all know that, but the last line is the tube, but there is a 2nd line of defense that occurs after the tire but before the tube, and that is a tire liner.
First off, a slime tube weighs around 172 grams each.
A Clear Motion Rhinodillos liner weighs about 95 grams each but is much more effective at stopping punctures than a slime tube. The Rhinodillo liner works far better than a Mr. Tuffy, I know this because I tested them both. First I took a pair of scissors to cut them both, and the Tuffy cut like butter, whereas the Rhino was much tougher to cut. Then I took a tack and drove it through the Tuffy fairly easily, but the Rhino bent the tack and did not penetrate it.
Since I started using the Rhinodillo liners in my commuter/RV camping bike and in the touring bike I haven't had a single flat in about 8 years. But the touring bike now has Schwalbe Amotion tires, so those by themselves are highly flat-resistant. Because I use a liner in those bikes, I use lightweight 65-gram butyl tubes. When added up my combination comes to 160 grams, not that much different than using a slime tube, but my flat protection is far better.
By using a liner instead of slime you eliminate the mess, you eliminate having to refresh the slime after 3 months thus increasing the weight of the tire/tube, and you eliminate clogged valves.
The Rhino liners will not chaff your tube causing a hole after a thousand miles or so because they use a soft end that prevents that, Tuffy liners do not do that.