I have found, with my Bobwhites, it does not take a ton more light to get them to lay in the winter. However the laying and fertility is not consistent unless you also had heat. 14+ hours of total daylight and temps above 50 at night, 60+ during the day.
The disadvantages are that you will have to maintain this heat all throughout winter and if you live in an area of cold winters, should you lose power at some point, these birds will not have acclimated to the cold and you may lose birds. So make sure to have back up heat available.
I like to give my birds a break from laying during the winter and allow the laying to stop for better over all health.