Cura g-code for nozzle wipe for maker select plus with BL touch 3.1

i have a maker select plus with bl touch 3.1 using ADVi3++ 4.0.6 everything is working just fine when i tried to add a nozzle wipe to clear the nozzle before printing i added this to my Cura Start G-Code
G28 ; home all axes
G1 Y-3.0 F500.0 ;move out of print volume
G1 X60.0 E9 F500.0 ; start purge
G1 X100 E12.5 F500.0 ; Finish purge line
everything worked as planned except that the purge started above the bed and just made more of a mess . should i have added a Z home command ?

Yes probably.

That would be G1 Z? What value should I use for Z or how would I calculate it?

My offsets for the BB Touch are X=-30 Y=-65 I don’t think my Z value can be 0. What can I do to get the correct value

It is the value you want. There is no calculation to do. Or maybe I do not understand your question.

If you want to raise the head above the bed of 1cm, the value is 10 (10 mm)

Sorry. I thought that the bl touch had changed the value of Z home because the extruder was above the bed when the filament came out. I made the mistake of adding the gcode to the end of what was there instead of replacing it

I have published a full example of starting g-code. You should look at it.

Could you please send a link. Thanks for all of your help