Adding hooks to TortoiseHg

you can put your .py wherever you like and use a full path to it. the syntax is then

[hooks] 
pretxncommit.myhook = python:/path/to/my.py:newbinsize

To enable in-process hooks in TortoiseHg you must put your *.py file into C:\Program Files\TortoiseHg\library.zip. TortoiseHg loads Python files from library.zip.

Reinstalling TortoiseHg will probably mean having to repeat this step.