Put very simply........, there have been a few articles about correctly fitting the fore-end on this forum. Be advised that the 4 to 7 lbs weight at the muzzle end of the fore-end is for a length of about 2" and not just at the tip. Also, it should sit in the middle of the channel and centre itself in the channel when you lift it left or right. The answer to the last question is simpler to explain. Use engineers blue.
Just a word of warning.......... If you're going to re-fit it, just go a tiny bit at a time and when you're removing the fore-end from the rifle after taking the rest of it apart, release it by trapping it gently at the rear top edges to break the taper between the butt socket and the draws.
Easy as you go..................