I wonder if it's overkill, or if it's even possible to know the on sale times & sell out times for the series... I think the first series sold out quickly. I don't know about the 2nd, but I know the 3rd was available for a while (at least a week or more. I believe from the 4th through the 7th (including Halloween releases), it was a matter of hours, and the 8th was a matter of a couple of weeks.
Here's what I've found so far on the Limited Edition sets sell out times:
PC1 sold out in roughly 10 hours (100 sets)
PC4 sold out in roughly 9 days (200 sets)
PC5 sold out in roughly 6.5 hours (250 sets)
PC7 sold out in roughly 3 hours (500 sets)
PC8 sold out in roughly 13 days (999 sets)