Use of G54-G59, G92 offsets

[mschoonmaker]

I'm quite new to the world of CNC offsets, and am looking for a little guidance on 2 items...

1. My CNC Router table does not have limit switches. so I use an Y/Y corner touch plate probe on one corner of my table. I prefer to set up the center of my table as the ZERO position (most of the time), So I'm planning on using G54 for this configuration. In macro programming (using A_Camera's probing screen) I would simply assign the known offset at that time, which allowed me to "Go To Zero" and the router collet would land on the dead center of the table. Now, I can't seem to grasp how I would accomplish the same thing using v2.113's probing process. Can anyone suggest where I'd place these X/Y offsets? the probing process overwrites the G54 offsets, so it's surely not that.

2. My second approach uses a laser crosshair that will be placed upon the center of my workpiece. When using this approach, there's no need to probe the corner of the table with the touch plate. I also know the specific offsets of the collet center to the crosshairs - I'm guessing this is a G92 type process? My concern with G92 is that the (G92) docs say

"The axis offsets are always specified in absolute values and effects all fixture coordinate systems."

I _think_ I'm looking for a RELATIVE offset from the current position (which has the laser crosshairs positioned over the target position). Also, how to implement this? Would I build a button and call a macro, or is something else "built-in"?

thanks for any input anyone can offer...