But the problem I am having is playing a chord in the left hand then an apregg. on the higher registers with that hand, while playing something in the same spot with my right hand.
I guess it's the high LH arpeggios that give you trouble, not the low (un-crossed) ones ?
There are 3 reasons that may make these difficult:
1) The stretch, as you have small hands
2) The fact that the LH must play over the right (though the distance is not great, that can't be the problem as you are not Terez
3) The high lying position of the LH, which perhaps necessitates a posture change
I recommend trying to find out which of these 3 aspects is causing you the most trouble, and practice them on their own. This is just an idea, I never tried something like this as these bars never gave me trouble. Sound like it might work though...