It would be amazing to be able to increase the size of the check boxes. I have assembly guys filling in forms with gloves on, and the boxes are tiny for them. They press the wrong boxes by accident.
Hey Sarah - worth playing with some CSS to get the size and spacing you need.
I'm guessing that you have a connected field displaying checkbox selections, and to add more space between each item (without changing the actual box size) try this changing the field number to yours:
#connection-picker-checkbox-field_XXX > div.control {padding-bottom:5px}
And to change the actual box size:
#connection-picker-checkbox-field_XXX > div.control > label > input[type=checkbox] {width:15px; height:15px}
One of Knack's benefits is being able to tweak this stuff to suit exactly what you want, so have a play with numbers to size and space the controls how you want.