Amnesia Fast-24hr lights

Seedsman has excellent customer service. I ordered Jack Herer Autos that never germinated and Seedsman sent out these Amnesia Fast seeds within the week. I am new to fast and auto flowering. I plan to let this plant take on it's own form and then once I see how it grows I can modify my grow techniques as needed. Looking forward to this one with a 24 hour light schedule and I am curious how much of a difference the amount of time on a Fast or Auto seed will do for its growth.