I do that in a different way than I do on 3x3 though. I usually do it by looking at blocks. For example, if there is a CEC block, I know that there cannot be another block (except for a j perm) for it not to have parity.
For example, I have particular trouble distinguishing E perm from what I will call "E parity"; I have to line up the edges to make sure it is one or the other.
Scroll about 2/3 of the way down.