I'd be happy with 1,200 ft plus. The model here is 220 CPS, the gold standard of "Billionaire's Row". It's directly on the park, so it really wouldn't need to go as high as Central Park Tower.
On the other hand, there's a tower planned directly south (41 W. 57) that will be at least 1,100 ft, and those Midtown views are precious as well.
We definitely wouldn't want two towers of basically the same height there.