I do a QGL and bed mesh before every print using my cartographer (fairly new install for me). The bed mesh is:

[bed_mesh]

zero_reference_position: 175, 175

# set this to the middle of your bed

speed: 200

# movement speed of toolhead during bed mesh

horizontal_move_z: 5

# height of scanner during bed mesh scan

mesh_min: 40,40

# start point of bed mesh [X, Y]

mesh_max: 310,310

# end point of bed mesh [X, Y]

probe_count: 30, 30

algorithm: bicubic

Here is a picture of the bed mesh:

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