Changes the size of the guiding box.
2=to: 2!:}Format: GUISIZE <npixels>
2=to: 2!:}Example: GUISIZE 30
2=to: 2!:}Default: npixels=15
2=to: 2!:}Range: 5 to 100
2=to: 2!:}Comments: This can be used to increase the size of the guiding box in bad seeing conditions.