Whenever I am an AR, I move 8m (not 5), usually to my left (though it doesn't matter which way you go, as long as both AR's don't end up opposite each other!). I find that from the mark to the back of the #8's feet is usually pretty close to 3m, so you go 5m beyond that. Don't hold your flag to indicate the line: use your other hand.I usually tell the ARs/TJs to go 5 meters to their right. That way one is covering each teams' offside line.
That's the way I was told to do it; ie if both TJs mark out the offside line to their left they should be diagonally from each other. The keyword is "diagonally" ie both TJs shouldn't be marking the same offside line.Whenever I am an AR, I move 8m (not 5), usually to my left (though it doesn't matter which way you go, as long as both AR's don't end up opposite each other!). ..
We have moved away from this now, and I believe rightly so.
We no longer police the attackers offside line, generally there is no point, they are only cutting their own options down if they cross it, so it's never material.
Far TJ will police the offside line of the defence, near TJ will stand level with scrum to keep an eye on the opposite side for the ref.
If the Scrum is in the middle, the TJ on the refs side will police the offside.
It works very well.
We no longer police the attackers offside line, generally there is no point, they are only cutting their own options down if they cross it, so it's never material.