It is unrealistic to believe that the dogs will never get into an argument - they will, just like human siblings will argue with one another. Most arguments will be diffused by the dogs and do not require us to butt in. Do not panic if they do become heated, you can move them away from one another using the trailing line, by making a noise to distract them, or if it's really heated, using a glass of water to confuse them.
Watch your reactions to interactions and arguements. If you are constantly anxious of the dogs interacting they can pick up on this and they will also learn to be anxious about interacting with one another. It is important to keep positive and lighthearted about their interactions, the more carefree we are, the more carefree they will be.
It is recommended that their initial greeting is done with their trailing leads hanging loose. Tip: You can trigger aggression by tensing up or holding the leash too tight. Keep your leashes loose and if the dogs are tense you can easily step away before the dogs are too close to tangle. Don't walk straight towards another dog-just circle closer from the side and then walk side by side. If you are calm and find the posturing amusing, the dogs will sense they don't have to worry either.
If the dogs are starting to get over the top, are beginning to argue or get too heated you can use your body to block one dog from getting to the other. Take hold of the trailing line and stand in the dogs eyeline. They will try to look around you so be prepared to shuffle around until the dog is calmer. If the dog is finding it hard to settle back down perform a time out but shutting them into another room. Give them a good amount of time to settle before reintroducing. If they are het up, sent out for aa brief second and they come back in het up you haven't achieved anything.
Try not to control them with your hands or grabbing hold of the collar, as this will create a negative association of human hands coming towards them and could lead to you being bitten - this is called redirected frustration/aggression.