Centering your material in LaserGRBL.
Check out my custom buttons for LaserGRBL. They will help you setup your material better:
http://fileit360.com/?dl=45604ddc5534...

YoraHome 6550 Pro Laser:
https://yorahome.com/collections/diod...

Additional Link: http://fileit360.com/?dl=45604ddc5534...

NOTE: You cannot open the archive, you MUST import the buttons just like in the video.