Header says bounds are:
  SW: (-124.675492, 44.869141)
  NE: (-114.995021, 50.357256)

First 20 tiles and their ACTUAL geographic locations:
================================================================================

Tile #0: z=0 x=0 y=0 → Center: (0.0000°, 0.0000°)
Tile #1: z=1 x=0 y=0 → Center: (-90.0000°, 42.5256°)
Tile #2: z=2 x=0 y=1 → Center: (-135.0000°, 33.2566°)
Tile #3: z=3 x=1 y=2 → Center: (-112.5000°, 53.7466°)
Tile #4: z=4 x=2 y=5 → Center: (-123.7500°, 48.3782°)
Tile #5: z=5 x=5 y=10 → Center: (-118.1250°, 52.3495°)
Tile #6: z=5 x=5 y=11 → Center: (-118.1250°, 44.9512°)
Tile #7: z=5 x=4 y=11 → Center: (-129.3750°, 44.9512°)
Tile #8: z=6 x=11 y=21 → Center: (-115.3125°, 50.7026°)
Tile #9: z=6 x=10 y=21 → Center: (-120.9375°, 50.7026°)
Tile #10: z=6 x=10 y=22 → Center: (-120.9375°, 47.0058°)
Tile #11: z=6 x=11 y=22 → Center: (-115.3125°, 47.0058°)
Tile #12: z=6 x=11 y=23 → Center: (-115.3125°, 43.0345°)
Tile #13: z=6 x=10 y=23 → Center: (-120.9375°, 43.0345°)
Tile #14: z=6 x=9 y=23 → Center: (-126.5625°, 43.0345°)
Tile #15: z=6 x=9 y=22 → Center: (-126.5625°, 47.0058°)
Tile #16: z=7 x=23 y=43 → Center: (-113.9062°, 49.8295°)
Tile #17: z=7 x=22 y=43 → Center: (-116.7188°, 49.8295°)
Tile #18: z=7 x=21 y=43 → Center: (-119.5312°, 49.8295°)
Tile #19: z=7 x=20 y=43 → Center: (-122.3438°, 49.8295°)

================================================================================
ACTUAL coverage based on tile coordinates:
  SW: (-180.000000, -85.051129)
  NE: (180.000000, 85.051129)

Difference from header:
  Longitude off by: 55.32 degrees
  Latitude off by: 129.92 degrees