This mount should allow to mount the magnetic base to the BantaMount (thing:3543121).

Designed with TINKERCAD.

UPDATE:

I had this working since i designed it. Its stable enough to provide reliable results, as tested with marlin probe accuacy.

The main problem is that its not compatible with the stock firmware.
(I havent tested but offsets are big and you can only set z-offset)

Also on the right side you cant home without it crashing the bed.

In marlin you can easily adjust the probe offset, here are mine:
define X_PROBE_OFFSET_FROM_EXTRUDER 20 // X offset: -left +right [of the nozzle]
define Y_PROBE_OFFSET_FROM_EXTRUDER -13 // Y offset: -front +behind [the nozzle]
define Z_PROBE_OFFSET_FROM_EXTRUDER -25 // Z offset: -below +above [the nozzle]

How you configure Mesh-Bed-leveling is up to you. I will post my config below.

My Mesh Creation:
G28 #Home
G0 z50# Lift head a little bit
G0 x200 y200 #Move to middle of the bed, attach probe
G29 #Perform a Bed leveling with probe attached
M420 S # Load your new mesh
G28 #G0 z50 # G0 x200 y200 #Same as before to be safe, remove probe

Fine tuning in case your probe offset in firmware is not perfect:
G0 Z0 # Go to zero, try higher values to prevent crash
M206 Z-1 #To move up your Offset by 1mm
G0 Z1
G0 Z0 #Sometimes it will accept offset when you move up and down again

=> Do the papertest and testprint untill you are happy with your M206 Value.
M500 To save everything to Memory

Hope that helps.

By now i moved to a direct setup.
Big thanks for this thing: https://www.thingiverse.com/thing:3586698

//===========================================================================
//=============================== Bed Leveling ==============================
//===========================================================================
// @section calibrate

/**

• Choose one of the options below to enable G29 Bed Leveling. The parameters
• and behavior of G29 will change depending on your selection.
• If using a Probe for Z Homing, enable Z_SAFE_HOMING also!
• • AUTO_BED_LEVELING_3POINT
• Probe 3 arbitrary points on the bed (that aren't collinear)
• You specify the XY coordinates of all 3 points.
• The result is a single tilted plane. Best for a flat bed.
• • AUTO_BED_LEVELING_LINEAR
• Probe several points in a grid.
• You specify the rectangle and the density of sample points.
• The result is a single tilted plane. Best for a flat bed.
• • AUTO_BED_LEVELING_BILINEAR
• Probe several points in a grid.
• You specify the rectangle and the density of sample points.
• The result is a mesh, best for large or uneven beds.
• • AUTO_BED_LEVELING_UBL (Unified Bed Leveling)
• A comprehensive bed leveling system combining the features and benefits
• of other systems. UBL also includes integrated Mesh Generation, Mesh
• Validation and Mesh Editing systems.
• • MESH_BED_LEVELING
• Probe a grid manually
• The result is a mesh, suitable for large or uneven beds. (See BILINEAR.)
• For machines without a probe, Mesh Bed Leveling provides a method to perform
• leveling in steps so you can manually adjust the Z height at each grid-point.
• With an LCD controller the process is guided step-by-step.
  */
  //#define AUTO_BED_LEVELING_3POINT
  //#define AUTO_BED_LEVELING_LINEAR

  define AUTO_BED_LEVELING_BILINEAR

  //#define AUTO_BED_LEVELING_UBL
  //#define MESH_BED_LEVELING

/**

• Normally G28 leaves leveling disabled on completion. Enable
• this option to have G28 restore the prior leveling state.
  */

  define RESTORE_LEVELING_AFTER_G28

/**

• Enable detailed logging of G28, G29, M48, etc.
• Turn on with the command 'M111 S32'.
• NOTE: Requires a lot of PROGMEM!
  */
  //#define DEBUG_LEVELING_FEATURE

if ANY(MESH_BED_LEVELING, AUTO_BED_LEVELING_BILINEAR, AUTO_BED_LEVELING_UBL)

// Gradually reduce leveling correction until a set height is reached,
// at which point movement will be level to the machine's XY plane.
// The height can be set with M420 Z

define ENABLE_LEVELING_FADE_HEIGHT

// For Cartesian machines, instead of dividing moves on mesh boundaries,
// split up moves into short segments like a Delta. This follows the
// contours of the bed more closely than edge-to-edge straight moves.

define SEGMENT_LEVELED_MOVES

define LEVELED_SEGMENT_LENGTH 5.0 // (mm) Length of all segments (except the last one)

/**

• Enable the G26 Mesh Validation Pattern tool.
  */

  define G26_MESH_VALIDATION

  if ENABLED(G26_MESH_VALIDATION)

  define MESH_TEST_NOZZLE_SIZE 0.4 // (mm) Diameter of primary nozzle.

  define MESH_TEST_LAYER_HEIGHT 0.2 // (mm) Default layer height for the G26 Mesh Validation Tool.

  define MESH_TEST_HOTEND_TEMP 190 // (°C) Default nozzle temperature for the G26 Mesh Validation Tool.

  define MESH_TEST_BED_TEMP 60 // (°C) Default bed temperature for the G26 Mesh Validation Tool.

  define G26_XY_FEEDRATE 20 // (mm/s) Feedrate for XY Moves for the G26 Mesh Validation Tool.

  endif

endif

if EITHER(AUTO_BED_LEVELING_LINEAR, AUTO_BED_LEVELING_BILINEAR)

// Set the number of grid points per dimension.

define GRID_MAX_POINTS_X 10

define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X

// Set the boundaries for probing (where the probe can reach).
// AT I dont get the edge thing so absolute values

define LEFT_PROBE_BED_POSITION 10

define RIGHT_PROBE_BED_POSITION 365

define FRONT_PROBE_BED_POSITION 20

define BACK_PROBE_BED_POSITION 380

// Probe along the Y axis, advancing X after each column
//#define PROBE_Y_FIRST

if ENABLED(AUTO_BED_LEVELING_BILINEAR)

// Beyond the probed grid, continue the implied tilt?// Default is to maintain the height of the nearest edge.//#define EXTRAPOLATE_BEYOND_GRID//// Experimental Subdivision of the grid by Catmull-Rom method.// Synthesizes intermediate points to produce a more detailed mesh.////#define ABL_BILINEAR_SUBDIVISION#if ENABLED(ABL_BILINEAR_SUBDIVISION) // Number of subdivisions between probe points #define BILINEAR_SUBDIVISIONS 2#endif

endif

elif ENABLED(AUTO_BED_LEVELING_UBL)