GRBL Homing switch pull off distance

Running GRBL and trying to see if I can set a specific pull off distance for an individual axis?

I’m not sure if I can specify $27 x5,y10

Or something similar?

Nop. It’s a general distance. You can set is a startup Block with something like.

$N0=G0X5Y10
$N1=G92X0Y0Z0

Startup Blocks always run after successful homing.

The first command Will offset the machine. The second Will zero the current coordinate system (G92).
If you want something more permanent I thing Grbl Will store coordinate systems in eeprom.
Set for example G54 to your offset like
G10L2P0X5Y10Z0
Then make your startup Block like this

$N0=G54G0X0Y0

This Will displace the position to the 0 off that coordinate system. Remember. If you switch coordinate system your reference change.