Without digging through all the forum member's names, I don't know who I'm speaking with.
Looking at the photo engraving you posted on the inventables forum, it looks like you need to make some performance settings changes to grbl for Laser use.
$0=30 (step pulse, usec)
$1=255 (step idle delay, msec)
$10=18 (status report mask:00010010)
$11=0.005 (junction deviation, mm)
$120=8000.000 (x accel, mm/sec^2)<--------I use a 12000 accel setting here, but I have nema 17 steppers on our Shapeoko 2.
$121=8000.000 (y accel, mm/sec^2)<--------And here.
These changes can be made in the GRBL menu Edit Settings window after selecting the GRBL Settings button. Then save them to the laser.txt file.