[okayama]

1st scramble: D L2 D R2 U' L2 D U2 L2 B2 R2 B D R' F2 R B F' L R F'
1st solution (1-hour): D R2 D' R F D R' D' R D F R' B R F' R' B' D L' F2 R' B2 L2 U' F (25 moves)

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Here is 30 min backup solution (28 moves).

(Inverse)

2x2x2 block: R' L' F' D2 R' D' L
2x2x3 block: U B' L' B L

(Normal)
Pre-scramble: L' B' L B U' L' D R D2 F L R

More square: F R F'
All but 3 corners: U2 R2 U' R2 U R2 U' R' U'
Correction: L' B' L B U' L' D R D2 F L R

Insert at the beginning: R B R' F R B' R' F'

In the remaining time, I found the following solution.

(Inverse)

1st square: F' U L2 B2
2nd square: R F2
2x2x3 block: L D2

(Normal)
Pre-scramble: D2 L' F2 R' B2 L2 U' F

More square: D
More square: R2 D'
All but 3 corners: R F D R' D' R D R' * D'
Correction: D2 L' F2 R' B2 L2 U' F

Insert at *: R F R' B R F' R' B'