Rachmaninov's Second Piano Concerto 3rd Movement fingering suggestions

[tommyo]

I was just wondering if anyone could suggest the fingering they would use for bars 21-22 (quasi glissandro). I cannot deceide on a comfortable one yet.

[mussels_with_nutella]

My fingering is this one.
To "gliss" up:
Left hand: 5,1,4,3,2,1
Right hand: 1,2,1,2,3,4,5
Left hand: 5,4,3,1
Right hand: 1,2,1,2,3,4,5, (2 y 3)
To "gliss" down:
Right hand: 5,4,3,2,1,2,1
Left hand: 1,2,3,5
Right hand: 5,4,3,1,2,1
Left hand: 1,2,3,5
Right hand: 5,4,3,1,2,1
And the rest of the quasi glissando is for you

[mussels_with_nutella]

I have a little doubt. When you finish the quasi glissando going up and down section (the first two long bars), it is followed by a lot of bars which have identicals third and fourth note, but played with different hands.

Does it mean that you must play it first with left hand and then with the right one, or that you must play it just once but with the hand you want?