The weight of the line box, even fully loaded is so little that if you clip the cables either side then the box is adequately fixed without any strain on the cable.
I use the j501's all the time since they where first realised. Great boxes and look very good. I know that the line boxes are quicker and can do everything better etc but I've got use to using them, just my opinion.
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc