Clinicians can treat the majority soft tissue concerns with four "scaled to anatomy" IASTM instruments. For a given region you would usually only need to use a single tool. Within each tool (S) small, (M), medium, & (L) large you will have appropriately sized convexity, concavity, and prow.
As an example, when treating epicondylosis, you would likely choose a (S) small tool. Not only does the profile correctly fit the tissue, but the tool is easier to manipulate (more comfortable) for shorter strokes in "the pen hold." It may be tempting to use one sized tool for all anatomical areas of the body, but this quickly becomes tiring if you do myofascial treatments on several patients a day.
On bigger anatomy, you can do much longer and deeper strokes with an (L) bar in the quadriceps, hamstrings, or erector spinae. Using a small tool on large muscle/fascia groups would require you cover a lot more ground with shorter strokes and also require more pressing effort. The reverse is true on a small fibrous lesion along a tendon- trigger finger for instance, where it would be awkward to use a bulky instrument for fine detailed application.
The Trigger Point Tool is included in all clinical sets, because it adds so much more range and versatility of treatment. "Riving" is when you work parallel between fibers (think wrist extensors, or hamstrings) and is much more easily performed with a "ball end" vs. beveled edge. The "point" contact also gets easily under the SCM or Scapula where edges are hard to maneuver, and is easy to apply through cloths near sensitive areas like sternum, coccyx, and inguinal area.
The MyoBar style series you choose comes down to personal preference.
Do you prefer a few more contact features like the LRE (large radius edges) and integral profile ergonomics (Healing Edge) vs. streamlined simplicity and the red handled grips (R+)? Do you prefer the ambidexterity of double bevel or, are you used to single bevel GT profiles (G+)?