I think the other potential challenge you face is comparing data from two different power meters. I know that this is highly debatable, but many of the reviews show that the various power meters are perhaps not exactly the same from a consistency stand point (meaning they all read consistently when using one or the other for baseline purposes but that they read differently often enough when compared to each other). I could be wrong though.

I personally use a Stages and have been happy with it from a cost effective crank based option I just don't know that I would use it in addition to a different one if using the data from both as my guide to training. I would probably simply swap or use the tarmac on the trainer