Disney has never released counts. We generally believe SV rooms are about 20% of the resort - no Grand Villas.
Overall the resort has 97 dedicated studios, 130 dedicated one bedrooms, 149 lockoff two bedrooms and 7 Grand Villas (all Boardwalk View). If they are evenly distributed (except the GVs) you get about 19 dedicated studios, 26 dedicated one bedrooms and about 30 lockoffs - 75 rooms. Potentially, that is 50 studios - studios do book fastest.
When thinking about booking availability and the home resort window, I personally think its better to think about BW Standard View as a seperate resort - which makes it the smallest
DVC resort.