Correcting Z coordinates of a walk Cycle

Hi,
I made a walk cycle. I use it in NLA editor. I noticed that the character is too high (3 inch above the ground ). I tried to correct this using a variety of ways …
A) I Went to the graph editor and locked every curve except the Z coordinate and then : G-Y -0.1 to lower the Z curves. … the character exploded …
B) I tried to select all the bones and add keys frames with the right altitude but it will add a crazy number of useless Keyframes …
C) I could parent the character and lower it only during the walk … Every time I use the walk :frowning:
Is there an efficient way to do this ? ( outside of re-making my Walk Cycle …)
Thanks !