I've had good success with decals. I've only made about 15 pens, so if I can do it anyone can do it. I did have little bit of an issue with the decal creation. I had to print a sheet of about 6 to get one good one. I think the pens I did are posted in my photo album on the site.
Basically create the decal...to be safe I took a day to do this. Apply the decal and let it dry for about 24 hours, then coat with CA and polish.
You can get get white or clear decal paper. For UPS with brown and yellow, I would use clear.