yep, the last 2 posts... with one caveat... a new plug vs a used plug... the 1/4 turn caves the crush washer and if you are reusing a plug, the seal is already flat, you only want a 1/16 to an 1/8 of a turn after contact.. I call it a "snuggy", run the plug down by hand, take the socket and "snug" the plug down..
maybe a Wrenching 101 for sparkplug installs?