I think the tempo is fine - certainly no faster than this. Remember that this variation is sandwiched between two much more wild and Florestinean etudes, so you want to create a nice contrast. I like to think of it as a time of reflection and a brief moment of peace before the finale. Coming back to your recording, I think the rhythm of the melody in the RH sounds too rigid, as though you are keeping time with the LH and playing the RH to match, when in fact it should be the opposite. It is not necessary to play exactly 5 against 16, or whatever the case may be, and in fact you should not try to do this - the feeling that you create in the RH is much more important, since that's what everyone is listening to, and the LH is just there as background. It's difficult to pull this off well, but I think you're off to a good start.
Topic: Schumann Symphonic Etudes Var. IX