Ruder test - letters k f t v w z - problem letters in the 100-400 wght 144 opsz 0 grad 0 slnt

* r sidebearing clashes with z - kerning
* k feels awkwardly narrow given h n o
* f and t are very tight given the rest of the design and seem anomalous. set together tt ft or ff seem distracting. The combination of ss for example has none of this.
* lc i and l also need a little bit more space.
* rounds of b d p q also could use a just a touch more space to find in with the rest of the design.