Attached pic is what I use for my lathe screen and serves me well.
Buttons allow for Work Offset selection and current fixture values are 
shown for the selected offset. 
- Created a label, the value is   COSYS  to show current work offset 
- Added a button to  Open / Change Fixturing
  OEM-Code 122
-Added DRO’s for input of the offset values
  Standard Code 30
-Added buttons to be able to set / select what offset I want to use at any time
  Standard Code 33
How it works:
Select the offset you want to use / change by clicking one of the offset buttons
 ( never needed more than six offsets). You input  offset values in the DRO,s  
and they are changed/added to the table, then click the Open /Change Fixturing button 
and the table will open and you save the table. Note that you must open and save the 
table when the table is open, that’s just the way it is.. When you click one of the 
offset buttons, that offset it becomes the current work offset, is shown on the 
screen label and the values of the table are shown.
 
In use:
G54 is the default offset when Mach3 opens. So say I machine a part with gcode and 
want to duplicate the  piece, I just click the offset desired and rerun the same code.
Must add that it all depends on what you want to do and how you want to work.
RICH