Stack the 1-2-3 block on top of your flat bar. Probe to the flat bar for Z and then probe to the top of the 1-2-3 block. You could use either dimension of the block depending on how much Z travel you have.
Stack the 1-2-3 block on top of your flat bar. Probe to the flat bar for Z and then probe to the top of the 1-2-3 block. You could use either dimension of the block depending on how much Z travel you have.