As you can see in the graph above, it looks like the 4.7-inch iPhone 6 model is clearly and very much so in the lead. In fact towards the end of the graph you can actually see that there is a slight dip in iPhone 6 Plus sales. However like we said, this is an early report and is by no means indicative of the future sales of both units.
It should also be noted that the reason the 4.7-inch model is in the lead is because there is extremely limited supply of iPhone 6 Plus models at the moment. In fact last we checked, pre-orders of the iPhone 6 Plus had an estimated shipping time of 3-4 weeks, and just yesterday there were reports that stock of the iPhone 6 Plus would be severely constrained.
It could also be possible that the difference in price might put off some customers who feel that the difference in hardware might not necessarily be worth the extra money. In any case it will be interesting to see how this works out once supply becomes stable, but in the meantime it looks like the 4.7-inch iPhone 6 is in the lead.