The lamp will be on for 20 hours a day the whole time. I could crack the california hash plant seed I have (its femmed) and just let it veg over that 2 months the Roadrunner grows out then flower the CHP after I harvest the RoadRunner. It could be a real beast of a plant in the end. It wouldn't cost too much to build another bucket like the one I have and there already is a second pump installed in the reservoir. I have time to ponder that.
If you're planning on another scrog the longer vegetative period would be a plus - you could end up only needing the one plant to fill your entire screen area if you veg it long enough. And flowering a fully mature plant has a lot to be said for it. So does having a plant under the screen from day one (or very early at least). They REALLY branch when you train them from "birth."