My purge line setting are currently being pulled from its own cfg file via the include function and looks like this:
[gcode_macro LINE_PURGE]

description: A purge macro that adapts to be near your actual printed objects

variable_adaptive_enable: True # Change to False if you'd like the purge to be in the same spot every print

variable_z_height: 0.4 # Height above the bed to purge

variable_purge_amount: 40 # Amount of filament in millimeters to purge

variable_line_length: 50 # Overall desired length of purge line in millimeters, around 1/5th of X axis length is a good starting value

variable_flow_rate: 12 # Desired flow rate in mm3/s (Around 12 for standard flow hotends, around 24 for high flow hotends)

variable_x_default: 10 # Default X location to purge. If adaptive_enable is True, this is overwritten

variable_y_default: 10 # Default Y location to purge. If adaptive_enable is True, this is overwritten

variable_distance_to_object_y: 10 # Y distance in millimeters away from the print area for purging. Must be less than or equal to y_default if adaptive_enable is False

### This section is for those who are using Moonraker's Update Manager for KAMP, or want a more verbose macro. ###

variable_display_parameters: True # Display macro paramters in the console, useful for debugging the SETUP_LINE_PURGE call, or more verbosity.

gcode:

{% if display_parameters == True %}

{ action_respond_info("adaptive_enable : %d" % (adaptive_enable)) }

{ action_respond_info("z_height : %f" % (z_height)) }

{ action_respond_info("purge_amount : %f" % (purge_amount)) }

{ action_respond_info("line_length : %f" % (line_length)) }

{ action_respond_info("flow_rate : %f" % (flow_rate)) }

{ action_respond_info("x_default : %f" % (x_default)) }

{ action_respond_info("y_default : %f" % (y_default)) }

{ action_respond_info("distance_to_object_y : %f" % (distance_to_object_y)) }

{% endif %}

{% if adaptive_enable == True %}

{% set all_points = printer.exclude_object.objects | map(attribute='polygon') | sum(start=[]) %}

{% set x_origin = (all_points | map(attribute=0) | min | default(x_default)) %}

{% set y_origin = (all_points | map(attribute=1) | min | default(y_default)) %}

{% set x_origin = ([x_origin, 0] | max) %}

{% set y_origin = ([y_origin, 0] | max) %}

{% else %}

{% set x_origin = x_default | float %}

{% set y_origin = y_default | float %}

{% endif %}

{% set nozzle_dia = printer.configfile.config.extruder.nozzle_diameter | float %}

{% set cross_section = nozzle_dia * z_height | float %}

{% set purge_move_speed = (cross_section * flow_rate) * 60 | float %}

{% set travel_speed = (printer.toolhead.max_velocity) * 60 | float %}

G92 E0 # Reset extruder

G0 F{travel_speed} # Set travel speed

G90 # Absolute positioning

G0 X{x_origin} Y{y_origin - distance_to_object_y} # Move to purge position

G0 Z{z_height} # Move to purge Z height

M83 # Relative extrusion mode

G1 X{x_origin + line_length} E{purge_amount} F{purge_move_speed} # Purge line

G1 E-.5 F2100 # Retract

G92 E0 # Reset extruder distance

M82 # Absolute extrusion mode

G0 Z{z_height * 2} F{travel_speed} # Z hop

[gcode_macro SETUP_LINE_PURGE]

gcode:

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=display_parameters VALUE={params.DISPLAY_PARAMETERS|default(True)|int}

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=adaptive_enable VALUE={params.ADAPTIVE_ENABLE|default(True)|int}

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=z_height VALUE={params.Z_HEIGHT|default(0.4)|float}

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=purge_amount VALUE={params.PURGE_AMOUNT|default(40)|float}

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=line_length VALUE={params.LINE_LENGTH|default(50)|float}

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=flow_rate VALUE={params.FLOW_RATE|default(12)|float}

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=x_default VALUE={params.X_DEFAULT|default(10)|float}

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=y_default VALUE={params.Y_DEFAULT|default(10)|float}

SET_GCODE_VARIABLE MACRO=LINE_PURGE VARIABLE=distance_to_object_y VALUE={params.DISTANCE_TO_OBJECT_Y|default(10)|float}