The Certified Mail Labels.com Single Label interface allows you to set defaults for each Mailing Profile. To do this, next time you create a label with the settings you want to use as your default, when you get to Step 3, check the box that says "Save as default for this Mail Profile" before you click "Purchase & Print." That's it!
After you create a label using those options, and you checked the box to save those options as your default, the next time you choose that Mailing Profile on Step 1, the mail options on Step 3 will automatically populate.