Cancelled events and regional qualifying spots

If an event is cancelled (due to weather) what happens to those regional event qualifying spots? Do they go into the pool that will pull from the overall skills rankings at the end of the season?

Also, is there any way to know how many unallocated spots a region has that will pull from the overall skills standings?

First question. Long Answer : for any empty spots for a worlds qualifying event the empty spots will be filled by the skills list. Short answer : yea.

My suggestion for your second question is to do the math and look at double qualifications. It might not be perfect but it gives great results.