I would gradually switch it to 18-20 hours per day by the end of week 2 or 3. Gotta let it sleep - stressed plants have a higher rate of turning male. And 70 watts incandescent is fine for now, but a good bluish fluorescent works great as a veg light to supplement the sun. Compact fluorescents are pretty cheap now; if it lists a spectrum choose as close to 7000 Kelvin as possible for veg. Your plant will enjoy 2 CFL's (100W equiv.) to replace those incandescents. Also, shiny foil is good to reflect stray light back to your plant, but if your walls are painted in "flat white" then they're already plenty reflective and you don't need the foil.