Need help on setting up Closet grow!

Closet is 9 feet tall but with the shelf on 2 sides of the wall im left with 6 feet 6 inchs tall to the shelf, 4'9 wide and 4 feet deep, What is the best setup for lights and cooling to end up with the most bud??? i already have a 8 bulb t5 pannel vegging a couple plants in my garage but i wana grow and flower everything in my closet Any Suggestions!???? Thanks

Invest in a 600 watt hid system for that big of an area or divide it into 2 and veg.and flower all year round