Left hand octave runs in Schubert's Wanderer fantasy

[hkilhamn]

I'm currently working on Schubert's wanderer fantasy, and there's a few bars in the end of the first movement where the left hand has c-d-eb-f-g in octaves in semi-quavers which is really hard if you have a quite slow Allegro, and If you take a fast Allegro it's feels almost impossible! I want to play it at a rather fast speed (go light on Schubert's 'ma non troppo' tempo marking) because I think the music deserves it. Does anyone have any suggestions how to practice these octave runs to make them work?

I'm actually considering doing like Brendel, just skip the octave and play only one voice in the left, but do the octaves in the right. But is he really allowed to do that?  
 

Thanks for responses / Henrik