I am a bit ashamed to say that the only time I use watermarks in a promo mix is to cover up little mistakes. I try not to do it too much, but in my RBMA mix I used the following voiceover twice
Soundcloud
I recorded straight off my mixer into adobe audition (single stereo channel). I don't have a vocal mic to record with, so I used my field recorder. I copied the file from the field recorder to my hard drive, and then did the effects direct through Audition. I pitched it down about 4 semitones I think, maybe more (without locking the time, so it would be longer). Then I normalized it and put it through slight EQ, slight distortion, and quite heavy compression (I don't know why I compressed so hard, in hindsight). Next I added ~5 seconds of silence on the end, and applied an echo effect where the highs would come off in the feedback. Finally, drenched it in reverb (too much, in hindsight). In Audition, you can do a "mix-paste", where you can mix one audio file directly into another and apply a fade-in/out to the pasted audio. Also, you set the levels of the mix by trial and error (original 40%, pasted 60% is about where I think I put it).
This whole process could be easily done in a multitrack setting, but I just did it as a quick&dirty bandaid for my (ocassionally) shitty mixing skills.