Question about practicum structure

Trying to hammer out my elementary observational practicum schedule with my mentor teacher, and she has basically said “whatever works” in terms of hours. So I wanted to ask people who have been here what worked for them.

For your student practicum (not student teaching), did you observe onsite for a few hours of the same day each week, or a whole class day at a time? How did you format your schedule?

ETA: This is a self-contained, lower-elementary general education classroom.