I promised this a couple weeks ago, so here it is:
According to city records the combined parcels that make up the BART lot make up some 8-9 acres, 10-11 acres including some the extra streets that run through the lot. The neighborhood northeast of the ballpark has no real buffer separating it from the lot aside from some small auto shop/garage-type buildings. Residents there would be impacted by noise and possibly light pollution. The only ways to orient the field are north (shown), east (similar to the Coliseum's field orientation), or south/southeast (field facing Hegenberger Road).