Personally I would do the 29 nights to get:

1. Free night in a $500+ hotel
2. 2 Suite upgrades
3. Concierge
4. Bonus points on October-November stays

But if that's not tempting enough, I would certainly put as many of the 20 nights into 2024 as possible - helping for requalification.

You can't rely on doing a fast track every year, so sooner or later you will have to do 60 nights in a calendar year. Plus if you do 60 this year, you would still have the fast track available for autumn 2024 when this promo comes back around...