Here are the setting changes I make for increasing the performance to raster laser engrave photos.
$0=30 (step pulse, usec)
$1=255 (step idle delay, msec)
$10=18 (status report mask:00010010)
$11=0.005 (junction deviation, mm)
$110=5080.000 (x max rate, mm/min)
$111=5080.000 (y max rate, mm/min)
Here are the acceleration settings for the X-Carve with nema 23 steppers as recommended by J-Tech Photonics.
$120=8000.000 (x accel, mm/sec^2)
$121=8000.000 (y accel, mm/sec^2)
Our Shapeoko 2 6W laser engraver with nema 17 steppers and Kevlar reinforced timing belts, the X&Y axis accelerations are set at max.
$120=12000.000 (x accel, mm/sec^2)
$121=12000.000 (y accel, mm/sec^2)
All other grbl settings for the Laser or Spindle Mode are the same, except the $30, $31 for the maximum & minimum PWM values & $32 for enabling/disabling the Laser Mode.
In the PicSender GRBL menu, the settings can be changed easy and saved for the different modes with two separate text files Spindle.txt & Laser.txt. Then, when switching modes, the settings will automatically change in Larry's grbl 1.0c.