Frankly, both are incredibly easy to get a FP+ for any time, so it really doesn't matter. Kali line has a huge ebb and flow during summer. First thing in the morning it's short. From roughly 10am-3pm it's really long. Then it drops back down to near nothing. Dinosaur usually has a short line most times, unless the weather is bad or other attractions are down.
Just pick whichever, it really is 6 of one and half dozen of the other.