That flux will work fine, but you only have to use it with the silver alloy:
Airgas - HAR4031 - 1/16" Harris® Safety-Silv® 40 High Silver Brazing Alloy Wire 1 Troy Ounce Pack (Prices are subject to change without notice due to raw materials cost volatility)
The CuP rods are flat and will mix well with the Safety-silv:
Airgas - RAD64001758 - .050" X 1/8" Diameter Radnor® by Harris® Stay-Silv® 5 Silver Solder Job Pak (prices are subject to change without notice due to raw materials cost volatility)
If you are joining copper to copper, the bare bronze(CuP) rods work well without flux. This eliminates chance of contamination and the need for flux removal. You can use the white flux with it if you want to, but inert shielding gas is still needed on the inside of the piping to prevent smut formation (another form of contamination). If you have brazed steel or aluminum before, this process is (much) easier than either of them. Even brazing copper to bronze or brass is easier with the silver alloy.