IE - I've sketched up a few single fins ideas over time. One direction of course is lots of rudder and some subfin for aerobatic gyrations. The other is the cleanliness of a single center solid fin of required area only.
With a delta if your going to use a rudder I would do a setup similar to a Yak where the longest cord is down low. Just a note of something I have seen, for some reason a sweptback rudder doesn't work well with a delta so if you do add a rudder keep the hinge line vertical. With just a fin something like CP did with his BOH would be cool.