Unless J have confused something, it is a D octave followed quickly by a c octave
I would use 1-5, 1-5 for both octaves.
There is really no space between the D and C that can be used: play the D octave and then move your entire hand down couple of mm to play the C octave. It can be done at lightening speed— and I’m really just an average pianist. There is no need to try to roll between the two octaves— since they are both natural keys, it would be problematic as you do need to strike the C’s
Have I misunderstood thd question/problem?