I didn’t realize just how useful learning all of these triad positions would be until they started clicking, particularly up and down between the three core shapes in a given key (root on string 2, 3, or 4). Beginning with the shape below as the I chord gives you a ton of options nearby. The ii, IV, and vi have multiple options that are easy to grab or switch between.
With a bassline or second harmony covering the low end, you can easily cycle through the upper extensions of the underlying chord (upper structure triads once you’re beyond R,3,5 if I recall correctly). Throw sus2 and sus4 in and your palette extends even further. I should probably record an audio example to demonstrate.
The best thing to me is that you can always map a diatonic mode back to a home Ionean key, so just knowing which I chord you refer back to means you can grab extensions up and down the neck. For instance, A Aeolian is just the sixth mode of C Major, so all of the triads will be the same as those in C. Even grabbing the C Maj triad just gives you an Am7 over an A bass note.
Pedal On 