There are a lot of variables to this scenario. 7th Sea 2E tries to meter out the action with bidding raises, although by and large I don't see the mechanic having an affect on things more so than other systems. For a starting group, I would expect any given encounter to last about an hour - social or combat. While every game's combat has stalling points based on the give and take, a lot of combats are decided before they start if only one side is formally trained (there are homebrews for partial "sword school" training, I believe some of them were put into later errata). A starter level game expects about two raises a round for a reasonably trained individuals, and as long as you avoid certain Virtues that create monstrous dice pools, the game should flow.
Your biggest stalling moments will be players figuring out more uses to raises than for the most obvious things like picking an attack. The game is designed to be more free form by even making NPC generation more spontaneous, and most actions resolved by predetermined success from rolls every round. Your players having experience will be incredibly helpful so that they will have a better understanding of how to pace the more "cinematic" bits that don't need rolls. 7th Sea 2e is an original system, which may trouble some players who like to metagame their actions towards their best rolls, but ultimately it will be up to you to have cues and opportunities at the ready (especially in the beginning) to show them what sorts of things they can do here versus other games.
