E2 isn't centered on the bed

[eduwes]

Print a 300x300 border with E1, leave that on the bed and print a 300x300 border with E2.

E2 is offset to the right.

#define X_MIN_POS -50
#define X2_MAX_POS X_BED_SIZE + 47

explains normal 3mm offset on hotends. I believe they need adjusted so that the offset is closer to 0