Are you using a recent version of Carbide Motion? If so, you have the capability to stop the carve, then restart it at whatever line number (of GCode) you are at now.
I don;t have CM open in front of me, so I may not name everything exactly
- Pause the carve
- Look for a status line that says what line you are on now, write that down,
- Stop the carve
- Adjust the bit and re-zero Z.
- Instead of ‘Run’, look for the button ‘Program Restart’
- Hit that, and it should ask you for the line number. Because of certain technical considerations, you should use a value about 20 less than the actual line number.
- Profit!