In terms of character design, some characters are defined by soft, flowing curves, while others are built with sharp, straight lines. Sakiko is definitely the former. Everything from her face shape and body proportions to her wavy twintails and stage outfit silhouette leans into a softer, rounder, and more voluptuous aesthetic.
In contrast, Uika is designed primarily with straight lines. Curves are used very restrictively and only in essential areas (like her hair tips and chest) to keep her from looking too rigid, maintaining a perfectly balanced, slightly androgynous beauty. When you put their designs and color schemes together, it creates this incredibly satisfying dualismโ straight and curved, soft and hard. Itโs so visually pleasing that you just find yourself subconsciously drawn to them.
Also, speaking of their habits, while Sakiko loves to eat, Uika likely has to manage her physique as an idol. Plus, given how much she tends to overthink and drain herself mentally, it wouldn't be surprising if she's actually a light eater. But she definitely has amazing core strength. For example, in Episode 2, when she brought Sakiko home from the agency, she was the one carrying that heavy 10kg Roland VR-730 keyboard, while Sakiko only had to roll her suitcase and carry her doll case. (well, I always love her warm and gentle toward skk...
When it comes to Uika and Sakiko, I feel like who has the bigger bust changes depending on the artwork. But my headcanon is that Sakiko has bigger thighs and hips. The more we see Sakichan eating well, the more it feels like my headcanon might actually end up being true, which is nice to see.