I have a Raise3D Pro2, which if you are not aware, is one of the most overbuilt, overpriced printers that lacks some of the most basic features of an Ender costing 1/10th the price. One of which is ABL.
I wish to generate a mesh with a dial indicator temporarily attached to the carriage, and then apply that mesh to a G-code file.
How would one do such a thing once they have manually recoded the offset values for their grid?
That depends on the firmware, e.g. Marlin firmware can set a mesh through G-codes when the firmware is set to Unified Bed Levelling (UBL).
However, Raise3D is using a closed source of which is unknown on which the firmware is based. You can most probably not use the Marlin firmware commands.
If you want to adjust for a measured build plate surface geometry, you can always fall back on developing a software program to alter your created G-code source file.
If you map the surface you can describe the height as function of X, Y coordinates. The current height value should be compensated for that mesh. A relative simple program (or plugin, e.g. Python script) should be able to alter the first 10 mm of G-codes where you smooth out the mesh to zero compensation at 10 mm height. Basically this is what the Marlin firmware does, compensation for the surface geometry.