The proper way to set multiple tools is like this :-
Get into the habit of setting G54 or G55 or G56 etc.
The benefit of this is not realised until you try it. The biggest benefit is that the datum of the job can be moved with ease.
Set G54 X and Y axis to datum point on job.
Your Z axis datum is set by tool 1 or your datum tool e.g. a probe.
Touch your datum tool on top of job.
Set G54 Z to the reading in the Z axis machine dro
Zero out on top of job with above tool.
Load next tool.
Your tool offset is the difference in length between the datum tool and this tool.
Touch on same face, the reading in the Z dro is the offset of this tool, enter this in the offset table for this tool.
Repeat above line for all tools.
If more material has to be removed from face of job then the machine Z datum needs to be moved down. e.g. increase the value of Z in G54 fixture offset
Note
if your datum tool is not the first cutting tool then tool 1 will have an offset, if tool 1 is your datum tool then it will have an offset of zero.
Graham.