How did I reach the speed in this scale when I played it many years ago?
First I used paralell sets. You may wish to know what they are in Chang`s book you can download free.
The idea is: when you play 2 notes in unison, the speed between these 2 notes is infinite because you spend zero seconds to play from one to another. But, if you have one of the fingers a bit higher than the other, you go from infinite speed to a bit less speed,l OK? So, you go from infinite speed to finite but very fast speed. This is the way your mind "understands". So, you can try this. You choose for example fingers 1 2 3, you play them 10 times in unisson and then 10 times with your 1 finger down, your finger 2 one or 2 milimeters higher and 3 one or 2 mm higher then 2. And you let your 3 fingers fall in the keyboard. This is very easy to do.
After this, you play 1 2 3 4 in same way.
After, the transition 3-1 (E - F)
And the scale is complete, very fast...

But with this method may be you cant reach the necessary eveness.
To get it, I used to play 10 times 123-4 - 321 - 123-4 ... after, 12345 - 54321, 123456-654321... 2 octaves
Ascending and descending.
Last but not least, the transition between the last notes ascending to the first notes descending. Here, a slightly rotation of your hand helps a lot. When ascending, rotate your hand to the right; descending, to the left. Only in the transition: C sharp- D sharp- E (rotation to the right); E- D sharp - C sharp (rotation to the left).
But it is not the end... before this 35 notes cadenza, you have a very little scale beggining in D sharp. After you are abble to play the great cadenza, you must try to join both scales. Why? Because you need to teach your mind to play them sequencly.
Doing so, you`ll reach the goal in more or less one month.
I must apolodgize my uggly English. I`m not a native...
Best wishes
Rui