There's not enough time in the world to worry about double clutching.
I used to try to double clutch constantly before rallyX, in rallyX I realized, no amount of double clutching is going to get me from 2nd to first easily.
If you're driving "correctly," meaning downshifting at the last possible moment before the corner, it'll go in just fine without the double clutch. Just depress the clutch, blip the throttle, jam it in gear. All you should be worried about is the engine winding up if the revs are too low. If you're worried about wearing the clutch and the synchros so much, you probably just shouldn't drive the car that way.