To be honest, I'd give it a 60:40 weighting of being the lead market, but I'm no expert, it's just an opinion! I've tried trading using this as an indicator and it doesn't really work; in reality each market has to be traded on it's own merits.
Right now each market appears to have a distinct EW pattern and whilst they sometimes converge they don't follow identical paths. Take the Ftse, which retraces a perfect 61.8% to it's low last March, making a new multi-year low in the process of an impulsive wave down. The Dow was in a corrective B-wave in the same time period. By default, if there is to be any convergence now, the Ftse has to complete a full ABC whilst the Dow completes its C-wave. Hope this makes sense, but if not just say so and I'll write it in more detail.