o.O idk who taught you how to downshift, cuz that's not the way I do it haha.
Technically you are rev matching right, because all you are doing when you are rev matching is blipping the throttle up to an appropriate RPM for your speed and gear and then engaging the clutch.
Engaging the clutch slowly kind of defeats the purpose of bringing your RPM up because of the time it takes to let it out, and waiting to bring your revolutions down to below road speed is just kind of a waste as well.
As far as double clutch downshifting your technique could use a bit of practice. The way I downshift is as follows and takes place in the same time it would take for me to upshift.
Blip Throttle up a couple RPM depending on speed and gear
Engage Clutch almost before i'm done blipping
Back on Throttle
And the same technique goes for Heel-Toe downshifting except you incorporate the use of the brake
I Hope I answered your question/ ^_^