This style progress bar -- with the bubbling loading -- is what we would want for the tiered level progress bar. The liquid would be coffee coloured and the bar would lie horizontally.
A sexy progress bar for flights (can be adapted for other circumstances). It features overdue custom design elements.
Having a loader bar that includes diagonal lines would be something to consider for the final that could twirl around the rounded rectangular shape.
The 75 Inspiring Examples of Beautiful Loading Bar Designs - Progress Bar by Nina Geometrieva.