Boil the zest from about 2 to 4 oranges in the last 10 to 15 min, not too much longer or you might evaporate off the aroma.
I did that with my Belgian dubbel that I'm bottling in 2 days. It has a light orange taste, wish I had used 3 oranges instead of 2.
I bet 2 would be fine for a wit.
Here's a tip, use a vegetable peeler to cut the zest off, not a zester, that way the large chunks are easily removed, and try to avoid the white part, it will make it taste sour.
I also used .4 oz of coriander and every taste so far it was really overpowering, it still has some time to calm down though, not worried.