RIF- Reading Is Fundamental
All your questions are specifically answered in the convieniently placed manual in front of the seat next to you (read: the gove compartment).
In there you will find the torque specs, procedure and even the proper plugs by model number including heat range and gap that are appropiate to your car.
Never specified what engine you were running but on my 93 KA, a gap of 1-1.1 mm is spec. Found out the plugs I just replaced were two heat ranges colder than stock, and so far I have not nocticed a difference running the normal range plug I installed.
Here's a very good webpage on
heat ranges