Custom probing points MK52 bed (no replies)

Hi, I have been figuring out that I'm doing something wrong. Using a custom built Prusa MK2S with a MK52 heated bed.

I'm using #define AUTO_BED_LEVELING_BILINEAR in Marlin 2.0.6.1 and need to define four spots for the machine to probe because I'm using an MK52 bed which has magnets that interfere with the readings of the PINDA probe.

I've found a guide that says I need to set these values:

#define LEFT_PROBE_BED_POSITION 0
#define RIGHT_PROBE_BED_POSITION 225
#define BACK_PROBE_BED_POSITION 278
#define FRONT_PROBE_BED_POSITION 0

But these values don't exist in my Marlin install.

First of all I want to know, in able to do a bed leveling at the beginning of each print I use G29, it now probes 9 points on the bed. This kinda works, but I'm getting slight errors that make the first layer print badly. I'm using AUTO_BED_LEVELING_BILINEAR and I want the printer to probe four pre-defined spots on the MK52 bed so that I can avoid the magnetic interference.

Am I even using the correct bed leveling method? And where can I set the predefined probing positions? I hope someone knows the answer.