Already this is an amusing thread, and it is just getting started.
But while we snicker, you have raised a question that is hard to answer. Now I am not sure what you are saying when you say "a jockless format". Does that mean basically un-interrupted music with a stop-set every so often? Is there "noise and distraction" mixed in with the music?
There was a time in radio when contests and promotions were really big events, noisy events, with lots of hoopla. In the cities it meant rating season was taking place. Out in the small markets it meant we nabobs were playing monkey-see, monkey-do. Radio overall was much more subdued in that era (I'm talking several decades back) and I worked for a very successful operator who refused to run any stunts, contests, give-aways, etc. He forced us to think about "what do our listeners tune in for; let's do that well, do that better."
The next guy I worked for ran a lot of quiet little games and contests. Events that rewarded the listener with, with, well.... chicken feed. His attitude was that some people like puzzles and games. Quietly give them something to feed their habit but do it without stirring up the people who look upon a promotion as a noisy, obnoxious interruption of their listening pleasure.
Do you begin to get the drift of where I'm going? Look at the rest of what you do on the air. Your promotions should simply be appropriate for "all the rest of the decors in your room" to use a home decorator's concept.