Shop light fixtures are great for young clones and seedlings, but keeping them within effective range of a mature plant can get tricky. A four foot plant, flowered with your shop lamp, will yield about the top 6" of plant, if the light is above the plants. All else will be too far away, and thusly have insufficient lighting. The problem I had with the side-light CFL lights, was that heat rises, and since you have to 'snug' them in to be effective, it can bake anything above it. (other branches, fan leaves)

Those spotlamps seem to give more heat than lumens, too. Not good for a closet grow. A 250w HPS would work much better, with some ventilation and air circulation inherently required. A 400w would be optimal, but it would come with a serious heat problem you'd have to look into solving, prior to purchase. Plus, you can veg with HPS if need be, or use one of those switchable ballast systems.

Your disappointments grow in direct proportion to your expectations...
...Yields are irrelevant. Results are relevant. (you'll find out yield, when you reach your first harvest at full maturity) :jointsmile: