1) See http://communities.ptc.com/thread/32643
Any option that is in a config.pro file will be replaced with the setting for the same option in a config.pro file that is read later.
If the loadpoint/text/config.pro has mapkey pp and startup directory/config.pro has mapkey pp then the definition in the startup directory for pp will be the one Pro/E uses.
2) drawing .dtl settings are not available on a sheet-by-sheet basis. While it seems like that would be nice sometimes, imagine the difficulty of managing all the various options on each sheet of a dozen sheet drawing.
The d.dtl imension text size setting just sets the default - you can change the dimension text size after the dimension is created.