That's a tough one. For us Tink is the slightly higher priority since she regularly has new movies coming out.
For today Touring Plans is predicting the waits to be longer for Tink (peaking at 4pm at 75 min wait, whereas they predict C/R to peak at a 54 min wait at 4pm). But I don't know if that's based just on one day's worth of data, and if so, how accurate it is.
I guess I'd suggest going first thing to whichever character you don't have a FP for. The upside to going to Tink first is that you wouldn't be part of the mass of people walking to Fantasyland at RD. Also, it's on the way, as opposed to having to walk from the back of the park to the front just to make your Tink FP later in the day. The downside is that Tink doesn't start meeting until 9:15, so you'd be wasting a bit of time.
I am by no means an expert on any of this though...