There are two 1 oz. loads in this list of archived loads by the Old Curmudgeon of BP. Little quicker, but a drop in powder charge would slow it down. Chronographed loads typically aren't as fast when I've shot them.
https://www.ballisticproducts.com/load14_07_11.htm
In the BP Advantages manual I glanced at over 75 loads in 20 ga. 2.75" 1 oz. with a wide range of velocity and pressures. My experience with BP loads is that they will have at least one component not in your loading cabinet.