What the tall guy posts are accurate to show what the reserves currently are each month.
After that, there are projections based on hiring and class size. In 2014 and 2015, there were new hires finishing IOE and immediately getting a line in the junior bases. Other people were sitting reserve for 2-3 months or less in CLT.
Just think of it this way... once enough pilots are hired behind you to fill the reserve slots, you will get a line. There is not a shortage of flying or airplanes.
If we are hiring 25 per class, then in 4 months you will have 200 pilots junior to you. How many reserve FOs will we need as a company? Not too many more than that. in junior bases, it will be less. (Provided classes are still full).