The Stand down (I believe) comes into effect immediately. If you've left the links within the last 24 months, you either need to re-join the Links (yea right) or wait out the stand down period.
As for numbers, a lot will depend on how many Link Pilots (beyond the 32 mentioned) get starts. The more jobs that go to externals, the more the "Tag and Release" Pilots back up. Ideally, the Company wants to give courses to Tagged Link Pilots within 3 years of going on the list, but if the numbers get too large that wont (cant) happen. Assuming there will be 130 Tagged Link Pilots, and the Links can only release 50 per year, then by June the list will already be more than 2 years long.
So it's a balancing act based on Jet Fleet demand. Once we have a queue of Link Pilots on reserved numbers, can they be released to keep up with Jet demand? If yes, no externals hired. If no, externals will still be required, and for each hired another 3 Link Pilots get numbers.