I have the Eflite pitch guage too. Heres how to use it with the plastiblades.
You know that old refrigerator box in the garage stuffed full of replacement parts cardboard tags? Well heres what ya do with that other than stare and cry .
Just cut out two pieces of the folded side of the label and put one each on the leading and trailing edges of the blades and slide the guage on top of them. Keeps the pitch guage lined up while taking up the slack. Works like a charm!