God's number for corners?

[guysensei1]

3x3, edged solved, corners not. What's God's number in this case? I've messed around and got a 17 move position which may or may not be optimal,
F U B D F2 R2 D L2 U2 F D2 R2 U' L2 F2 U2 F'

Any thoughts from the experts?

 

[cuBerBruce]

3x3, edged solved, corners not. What's God's number in this case? I've messed around and got a 17 move position which may or may not be optimal,
F U B D F2 R2 D L2 U2 F D2 R2 U' L2 F2 U2 F'

Any thoughts from the experts?

Cube Explorer confirms your position requires 17 face turns. So 17 is a lower bound.

For QTM, it is 22. This was used to prove 40q as an upper bound for the whole cube back in 2005.