Double clutching works if you do it right. Coming out of gear, let the clutch out in neutral while the engine windmills down, then press the clutch and go to the next gear. It's a skill that demands timing and practice. When you learn the RPM's in all the gears, you can shift without the clutch better than with it.
As for rev's, don't go over about 3000 if you want it to last.