Yes, the main building height of WG looks fairly locked in. How silly would it be to be just as silly or more silly than other skyscrapers with even higher skinny spire height ratios already built? But anyway, let's look at what is already out there and see what we can find.
Saleforce Tower as we know it is currently set at:
912' = roof (zoning 1000')
970' = top of mechanical penthouse
1070 = top of structure (crown)
Look here:
http://www.thenextmiami.com/faa-appr...lest-building/
...And here: examine Attachments E 06 to 08
http://sfocii.org/meeting/commission...y-19-2016-2016
I believe those are all current 'roof' heights in Attachment E 06, but I'm not certain about Salesforce, and which of the above listed heights it actually corresponds to. It almost seems as if Parcel F was increased to compensate. The renderings look taller though.
Please note that no height changes have been officially announced yet.