I haven't actually played with printing presets, but I would do the following:
1) Make the changes I want and save the preset as "New."
2) Delete the preset named "Standard."
At this point you would be done as only one preset exists for the print dialogue to display, but I'm picky about things, so…
3) Rename "New" to "Standard."
Now, again, only one preset exists for the print dialogue to use. The only unknown I can see is if you are able to delete the existing preset; Apple may not intend you to do this, but I don't see why.