TLDR:
This would keep box sizes of Pd <= 0.47:
"7 12" on Linux and Mac
"7 13" on Windows
This is more likely related to platform margins and with the newer version of Tk, the metrics might be slightly different. Also, the zoom font sizing change may have lead to this as well.
If this can't be adjusted, it would be good to know if the _new_ box
sizes will be the canonical sizes.
Was there a canonical size before? We don't even have the same font on all platforms yet. I wouldn't plan on pixel perfect sizing yet...
It's way more than changing just the numbers in pd-gui.tcl and making per-platform metric numbers is probably a hack at best and headache at worst. In either case, IMO it's a lot of work and testing and thus may not happen *right now*.