By cycling the reps do you mean go through fives, triples and singles? So as an example I get stuck on fives, move to triples, get stuck in triples and mine to singles. Once this has run out I go back and try the set of fives where I was previously stuck?
As for the light deadlift day, I assumed that would be 80% of whatever your last heavy deadlift was?
With the PCs am I just doing them once a week or should I be doing a few sets on my light deadlift day?