One way you can solve this problem is fit a swivel to the loop. Then take a piece of slightly lighter line about 200mm long and double it, tying a knot in the open end so you have a loop. Loop one end through your sinker and the other through your swivel. It works a treat, and if you are using spoons you're likely fishing rough ground? and therefore the lighter line busts off before you lose your rig if you do get snagged. Just check the loop every couple of casts to see if its worn out and replace it if necessary.