I think something a little finer grained may be better. Oak is very hard but with large open grain or pores. I suspect the paste will wind up in the pores with the hard raised surface bare.
With the water based pastes we use it is best to "raise the grain" before lapping (sanding) to it's final flatness otherwise the moisture in the pastes will raise it leaving a less than flat surface.
Sand you poplar, etc.. strop nice and flat then dampen lightly with a moist rag. Once dry there will be a pronounced rasing of the grain structure which is sanded off again. repeat once or twice before your finished and ready to paste.
Basswood was used in the past on all wood strops as well.
Tony