@jjarosz I sincerely thank you for having given all these explanations, I would never have been able to setup my second extruder on my Sovol SV02 without you.
For people who would like to switch to klipper with their SOVOL SV02, here are my settings :
Klipper Config : Klipper for SOVOL SV02 with BLTOUCH - Pastebin.com
Cura
; machine start code >>
G21 ;metric values
G28 ;home all
G90 ;absolute positioning
M107 ;start with the fan off
;G1 F2400 Z15.0 ;raise the nozzle 15mm
M140 S{material_bed_temperature}; Heat bed but do not wait
M109 S{material_print_temperature} ;Set Extruder Temperature and Wait
M190 S{material_bed_temperature}; Wait for bed temperature to reach target temp
G92 E0 ;reset extrusion distance
ACTIVATE_EXTRUDER EXTRUDER=extruder
; << machine start code
; machine end code >>
M104 S0; hotend off
M140 S0; bed off
G92 E0 ; reset extrusion distance
G1 F3000 E-5 ; retract
G91 ; relative positioning
G1 Z10 ; lift Z-axis
G90 ; absolute positioning
G92 E0 ; reset extrusion distance
G1 F3000 E-90; unload filament
G1 F3000 X0 Y240; move bed for easy part removal
M84; disable steppers
; << machine end code
; extruder start code >>
T0
G0 F4500 X{prime_tower_position_x} Y{prime_tower_position_y} ; move nozzle to prime tower center
#M211 X1 S0 ; disable SW endstop
G0 F3600 X310 ; move nozzle to purge position
G92 E0 ; reset extrusion distance
G1 F3000 E88 ; load filament
G92 E0 ; reset extrusion distance
G1 F250 E25 ; purge nozzle
G92 E0 ; reset extrusion distance
G1 F3000 E-3 ; retract
;G92 E0 ; reset extrusion distance
;M400 ; wait for everything to settle
G0 F3600 X{prime_tower_position_x} Y{prime_tower_position_y} ; move nozzle to prime tower center
#M211 X1 S1 ; enable SW endstop
; << extruder start code
; extruder end code >>
G92 E0 ; reset extrusion distance
G1 F1200 E-5 ;short retract
G0 F4500 X{prime_tower_position_x} Y{prime_tower_position_y} E-93; move nozzle to prime tower center
;G1 F3000 E-85 ; unload filament
G92 E0 ; reset extrusion distance
; << extruder end code
Extruder 2 is identical except T0 that must be changed to T1
Final important note : these scripts are adapted from ThKu’s and work with the excellent Purge Bucket designed by him here : Clip-On Purge Bucket / Wipe for Sovol SV02 by ThKu - Thingiverse