There probably isn't room for a second rack, you get your volume from hanging.
Most meats are fine on the hooks for the entire cook, but for brisket and pork butt it is recommended that you wrap and place on the grate to finish them off. However, I have read on this forum about cooking a brisket on the hooks the entire time and it turned out great.
I have several smokers, but default back to the pbc for quick, no fuss cooking. It is ready to roll in 20 minutes. It is also very hard to beat for the price.
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