Ran across a customer who was asking about wanting to use a custom printer preset as the default preset. Normally, OS X doesn't have any setting that you can use to do so, but I ran across a little trick that I still can't find any official documentation on, and yet seems to work.
- Start printing a document, edit your settings and save it as a preset if you haven't already (I recommend for all printers, but its your call).
- While keeping the dialog box open, hold the Option key and select your Preset, then print.
- By holding the Option key, it should adjust your settings to use your preset as the default for future jobs.
It seems to play well with my system, but I dont have any real guarantee that this works consistently. The alternative would be to enable the CUPS interface (navigate to http://localhost:631/printers/ and follow the instructions) to change settings that way, but most end users probably dont want to go down that rabbit hole...