The tuner could work well, But keep it simple! Start your tour with good wheels in good shape. Before you start, take the tuner and find what your spokes are now. Again, keep it simple. Just find the frequency that best describes what you've got; for the front wheel, NDS and DS, Write down the notes or frequencies.
Now you can use the tuner out on the road to assist with truing or for target tensions should you need to rebuild a wheel (assuming the same or similar gauge spokes). It will also tell you if a spoke is way off but you can probably hear that just tapping the spoke and its neighbors. (Hearing is one of those gifts most of us simply take for granted but not all have it or can hear but not distinguish pitches.)