That will be a perfect setup. I'd set the dead key around 6-7 watts and let it swing. You might find you have to turn your mike gain or mike down just a bit when using it as it will increase your transmitted audio. Keep watch on the tube to make sure the plates (metal part inside tube) do not turn red. The 6CA7 is a good tube and should provide many years of reliable service.
Just be careful not to drop it into the sweep tube amp without dropping the dead key or you will let the smoke out.
I dont think you want more than 2 or 3 watts DK.