When you turn the tone knob, is it a gradual increase/decrease, from '1 to 10', or does it all happen between '7 to 10' ?
On the attached diagram, the earth linking the 3 pots is the control plate itself. If the 'cheapo' pre-wired plate has a bad earth between the pots and the control plate, then the earth won't 'earth' properly, which will cause problems
Does the link from the bridge pot to the tone pot run between the end tab of the bridge pot to the middle tab of the tone pot
Post a picture of your finished work so we can see what's going on
[attachment=19480:Jazz_wires.JPG]