Three possible minimum hole sizes:

As per IPC 2222

Minimum Hole Size = Maximum Lead Diameter + 0.25mm
Minimum Hole Size = Maximum Lead Diameter + 0.20mm
Minimum Hole Size = Maximum Lead Diameter + 0.15mm

A Minimum Hole Size = 0.55mm + 0.25mm = 0.80mm
B Minimum Hole Size = 0.55mm + 0.20mm = 0.75mm
C Minimum Hole Size = 0.55mm + 0.15mm = 0.70mm

Level A = 0.80mm + (0.05 * 2) + 0.60mm = 1.50 mm
Level B = 0.75mm + (0.05 * 2) + 0.50mm = 1.35 mm
Level C = 0.70mm + (0.05 * 2) + 0.40mm = 1.20 mm