5. If the text is still difficult to read, tap the chevron in the upper left of the screen to return to the previous menu, where you can try enabling Bold Text using the toggle.
As with many Apple Watch features, you can also control the Text Size option in from your iPhone. Simply launch the Watch app, hit the My Watch tab at the bottom of the screen, then select Display & Brightness, where you'll find a similar slider to adjust the text size on your watch in real time.