I used this information, with some adjustments. I have the glass bed, with clips, two on "bottom" and two on "top", and one on "left" and one on "right" of the bed, I placed the printer nozzle to have the 0,0 at 14mm/14mm, and that gave me about 207x212mm of clear print space. I print a small line to the left just to make sure that there is filament into the nozzle when print starts. It is outside the virtual rectangle, and does not touch any of the paper clips.
I used this start g-code
G92 E0 ; Reset Extruder
G28 ; Home all axes
G1 Z2.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed
G1 X1 Y5 Z0.3 F5000.0 ; Move to start position
G1 X1 Y100.0 Z0.3 F1500.0 E7.5 ; Draw the first line
G1 X1.3 Y100.0 Z0.3 F5000.0 ; Move to side a little
G1 X1.3 Y5 Z0.3 F1500.0 E15 ; Draw the second line
G92 E0 ; Reset Extruder
G1 X7 Y5 Z0.3 F5000.0 ; Move over to prevent blob squish
G21 ;Set units to mm
G90 ;Absolute positioning. New printable area is 207 width x 212 depth
G1 Z2 F3000 ;Raise to dodge bed screws
G0 Y15 ;Move Y to 15
G0 X10 ;Move X to 10
G92 X0 Y0 Z2 ;Set this position as the new X/Y zero
G92 E0 ; Reset Extruder
