:O I struggled with that part all of September!
I tried to play the whole run in one beat with the metronome, guess, divide it into smaller polyrhythms.... it just drove me nuts. Rhythms really aren't my thing.
So I did it in a not-so smart way- mathematically. My teacher laughed when I showed her what I did.
I'm not recommending that you use it, just saying it worked for me.
First I practiced playing hands separately obviously and all that. Then I played 2 notes in the right hand for every left hand note and a triplet at the end, just so I was familiar with where the notes were.
Then I divided the tuplet up... which is the not so intelligent part

For the 11:6, I added 2 tick marks after every note in the right hand, which divides the right hand up into 33 spaces. I drew a line from the first note of the right hand and the first note in the left hand. Then I counted 5.5 spaces and connected it with the next note in the left hand... then I counted another 5.5 spaces... etc etc. I did the same with the 22:12, only I had to do it twice.
If this doesn't make any sense, I've got a picture... It's jsut that it's late and I'm too tired to find it.
The division wasn't so difficult, it took 2 minutes, but practising still was tough.
The point of me dividing it up isn't to know exactly which 1/66th of the measure to play the notes (obviously!), but just to know generally when the left hand and right hand are played. At first my rhythm was really off and wonky sounding because I was trying to fit the hands together, but eventually I evened it out and it became more natural and free over time. After that I just practised with the metronome to make sure that I was keeping a pulse and not randomly speeding up and slowing down to fit the notes in at the right time.