The recently developed moissanite anvil cell (MAC) has become a useful device for achieving both high-pressure and large sample volume in an anvil cell. We describe two improvements in the basic design of the MAC. First, the loading environment has been optimized by centering the load. Second, a variety of supported systems have been examined to provide anvil stability at high loads with large anvils. Sample volumes that are nearly three orders magnitude greater than allowed by conventional diamond anvil cells can be pressurized and characterized at ∼50 GPa.