This concept is based on the Skylab II concept, which proposes using a SLS propellant tank as the primary structure of a habitat. Common Habitat takes this a step further, proposing an interior architecture that is equally viable as a lunar surface hab, transit hab, and Mars surface hab, thus enabling a single development to support all three long duration habitat roles. Common Habitat has been pursued by the PI and co-investigators at MSFC and other centers in a spare time / funding available basis, often with heavy student intern support. Student resources have developed preliminary concepts, but these models must be refined to reflect accurate vehicle subsystems, utilities, stowage, workstations, and other crew systems. This investigation applies NASA civil servant and contractor expertise to correct errors in the most recent student concepts in order to prepare them for future human-in-the-loop evaluations to determine the most viable configuration for a Common Habitat. In prior studies there was never an opportunity to trade both crew size and internal orientation. Prior work has been a series of point designs with inconsistent design constraints, making apples to apples comparisons impossible. The most recent student work produced CAD models of four habitat variants for future use in a trade study, but the student products contain model construction and geometry errors, inaccurate subsystems design and placement, and unrealistic structural elements and outfitting. These must be corrected before the models can be moved into a VR environment for humanin- the-loop testing. Through consultation with SMEs throughout the Agency, the fidelity of these designs will be upgraded to a level of quality sufficient to make a comparative analysis of crew size sensitivity and internal orientation. The product of this activity is four upgraded CAD models, each reflecting a different configuration of the Common Habitat. One is a horizontal configuration using the full length of the SLS LOX tank. One is a vertical configuration using the same tank dimensions. The third is a horizontal configuration using a truncated SLS LOX tank (half the barrel length). The fourth is a vertical configuration of the half-length SLS LOX tank.