From what I understand, the watchfaces don't update until they get out of view and get redrawn. If you keep the screen on after a minute changes, the change is not reflected until you scroll and come back or let the screen go off. What I'm saying is, it would be as simple as adding the seconds to the face as the values are only read once and not every second, they would be shown static.
@IrisNebula it is exactly how I want it to implement, but with some changes we can also trigger the watchface to update as it is made in stopwatch feature.
We have gone off topic, but to clarify, we can change the font if we stay in the same dimensions but in order to make it bigger (as in taller letters) that would need modifications to the firmware which should better not be done.
So with that said, I've made mine bold (as well as the date) to match the weekday font and it looks nicer in my opinion, it's also easier to read if that was your intent with bigger numbers.
(The time is also custom, I plan to release my modifications as soon as I feel comfortable with them, I need to make some small changes still)