However the devs appear to be aiming to match XCode - for example font size = 8 in XCode is much smaller than in Carbon/Windows/Linux.
If you're using the trunk, you should be able to do it in the following manner:
uses ...
{$ifdef LCLCocoa}
, CocoaInt
{$endif};
initialization
{$ifdef LCLCocoa},
CocoaBasePPI := 72;
{$endif}
It will not help with designed controls, but changing font in run-time will match Xcode.
Starting with 1.8 release, the Cocoa (and Carbon) PPI is 96, rather than 72.
Thus LCL selected fonts of the a particular size (in points) would not match the same font and the same size selected in Xcode or TextView.
I was trying to resolve the issue on case-by-case basis, however cross-platform needs took over. And 96 ppi rule remains.
The code above however allows to switch Cocoa back from 96 to 72 for run-time.