According to the Orenda instructions, it's 1 pound per 2000 gallons (5 pounds per 10,000 gallons) without adding acid until you are done with the conversion.

Note this post where there might be a slow drop in CC over time.

You could do a bucket test for the percarbonate rather subjecting your entire pool to it. If it works for pool water in a bucket, it should work in the pool. You'd scale down to very small added quantities as a result. 0.016 ounces weight (somewhat less than 1/8th of a teaspoon, I think) of sodium percarbonate in 2 gallons.