I assume that air bags hold their air perfectly so that if I use them for leveling at campsites ... their lifting height would stay fixed at what I set it at when staying at any given campsite day after day.
The bags will hold the air pressure unless a line connection is not set correctly. Test them with a soapy solution and a spray bottle as you would test a tire. Mine would lose a little pressure over time when parked in my driveway for weeks or months at a time, I found that to be normal.
How you described the two air lines and switches is the way I did mine in the past. When using them that way to level the rig at a campsite, it might be all you need to do. Depending on the terrain of each site but most of time the bags did the trick.
