I am making a 20x40" coffee table, and will use (for the first time!) table
top fasteners. I have built several other tables, but have run the grain on
the sides vertical rather than horizontal so I could just glue the top on.

1) Since it is winter and the wood is presumably as small as it gets, I want
to just barely put the fasteners ( the offset clip things) in the slots on
the front and back, to allow room for the top to expand. The sides can be
in close, since they will only have to accomodate sideways motion. Right?

2) Does it matter how tight I have have the top to the apron, or do I have
to do it loosely to facilitate movement?

3) Since the wood should grow by 1/4" at most, could I glue the front and
use the fasteners on the sides and back? Or is that pressing my luck?