Those 48 inch shop fixtures will give more light for less initial investment, AND less ongoing consumption of electricity.
But mainly, they will put out more light, which the plants really need.
I've used a few dim, relatively inefficient CFL "spot bulbs", but only to start seedlings and only because I couldn't figure a way to hang the 4 foot shop fixtures. (And I already had some bright CFL bulbs and a "pole lamp".)
