They need 18 hours of light for the veg cycle even 24/7 light will work. 14 hours is not enough light for seedlings. Size difference is seedlings are not much to worry about. Most of the time the males are the first to grow and are the tallest ones. Not 100% of the time but I bet 90% of the time the tallest ones from seeds are males.

It takes about 30 day's from seed for all the antioxidants to mature before you can flower them if you want a descent crop anyway.