For your information rope halters with knotts on nose band doesnt cause pain. ....All the big trainers like clinton anderson, pat parelli use rope halters so id say can't be all bad. ...Horses kick and bite each other so I honestly dout
Slow down & think about it some more. Yes, of course rope halters with extra knots(what do you think the extra knots are there for??) or other equipment used harshly can cause pain. Just because some 'gurus' do something doesn't mean it's necessarily right for all, but I don't think the use of rope halters is what's being argued here anyway. Just because horses kick & bite eachother doesn't mean that we should aim to treat them that way, and just because they do that to eachother doesn't mean anything less is not painful.
Anyway... OP I disagree with using a bit(or other potentially harsh equipment) with a long rein when training a horse to lunge or such. The added rope length means added weight & leverage on the bit, so can have the effect of the horse becoming 'heavier' on the aids. I would only use a regular halter until the horse is well trained at least. For this reason I also disagree with using a heavy rope with a heavy clip, as some 'gurus' advocate too.
Agree basically with Equitate, that if you ask them to go out on a circle(or whatever... or dog pulling on a lead...) and they lean on the rope, if they continue this behaviour, it is due to the handler continuing to hang off the rope & allowing the horse to do that. Takes 2 to Tango.
So what do you do about it? First I'd teach the horse to do everything well & softly up close, before I test/reinforce it at a distance, as with lunging, so the horse is more likely to 'follow a feel' & not likely to hang off pressure anyway. Then if/when he does, I would be signalling for him to bring his head/FQ towards me a bit more, HQ away.
If he didn't listen to that, I would not be adverse to 'bumping' him with the lead. Tends to only need/want small 'bumps' to make it uncomfortable, rather than strongly 'jerking' the horse around. If that didn't have the desired effect, I'd stop the horse & go back to earlier lessons, as I'd be thinking something was missing there.