This paper presents a method for assessing the accuracy of dynamical measurements of protoplanetary disk gas masses using resolved (CO) spectral line data, accounting for observational limitations, measurement biases, and ambiguities in disk geometry and physical conditions. The method was tested on synthetic datasets and applied to archival ALMA observations of the MWC 480 disk. For massive disks (M_d/M* = 0.1), the method recovered true gas masses with little bias (<20%) and uncertainties within a factor of two (2σ). The gas surface density profiles were recovered with high fidelity. For lower mass disks (M_d/M* < 5%), the method becomes insensitive due to degeneracies in surface density profile parameters. Including multiple lines probing different vertical layers and improving associated tools could lower this threshold by another factor of ~2. The analysis was applied to MWC 480, yielding M_d = 0.13 ± 0.04 M_⊙ (M_d/M* = 7 ± 1%) and identifying kinematic substructures consistent with surface density gaps at 65 and 135 au. The results suggest that these dynamical measurements offer powerful new constraints for quantifying gas masses and surface densities at the high end of the M_d/M* distribution, serving as key benchmarks for detailed thermo-chemical modeling. The study addresses prospects for improvements and discusses caveats and limitations to guide future work. The paper also presents a detailed model of disk physical conditions, kinematics, and molecular abundances, and describes the process of converting these models into simulated datasets. The analysis of these datasets reveals the kinematic effects of self-gravity and pressure support, and demonstrates how these effects can be used to infer disk properties. The study highlights the importance of spatial resolution in kinematic measurements and the need for empirical corrections to account for beam-averaging effects. The results show that the method can accurately recover disk properties even with limited spatial resolution, but that biases can occur in the inner disk due to the averaging of intensity gradients. The study concludes that this method provides a promising new approach for accurately measuring disk gas masses and surface densities, with potential applications to a wide range of protoplanetary disks.This paper presents a method for assessing the accuracy of dynamical measurements of protoplanetary disk gas masses using resolved (CO) spectral line data, accounting for observational limitations, measurement biases, and ambiguities in disk geometry and physical conditions. The method was tested on synthetic datasets and applied to archival ALMA observations of the MWC 480 disk. For massive disks (M_d/M* = 0.1), the method recovered true gas masses with little bias (<20%) and uncertainties within a factor of two (2σ). The gas surface density profiles were recovered with high fidelity. For lower mass disks (M_d/M* < 5%), the method becomes insensitive due to degeneracies in surface density profile parameters. Including multiple lines probing different vertical layers and improving associated tools could lower this threshold by another factor of ~2. The analysis was applied to MWC 480, yielding M_d = 0.13 ± 0.04 M_⊙ (M_d/M* = 7 ± 1%) and identifying kinematic substructures consistent with surface density gaps at 65 and 135 au. The results suggest that these dynamical measurements offer powerful new constraints for quantifying gas masses and surface densities at the high end of the M_d/M* distribution, serving as key benchmarks for detailed thermo-chemical modeling. The study addresses prospects for improvements and discusses caveats and limitations to guide future work. The paper also presents a detailed model of disk physical conditions, kinematics, and molecular abundances, and describes the process of converting these models into simulated datasets. The analysis of these datasets reveals the kinematic effects of self-gravity and pressure support, and demonstrates how these effects can be used to infer disk properties. The study highlights the importance of spatial resolution in kinematic measurements and the need for empirical corrections to account for beam-averaging effects. The results show that the method can accurately recover disk properties even with limited spatial resolution, but that biases can occur in the inner disk due to the averaging of intensity gradients. The study concludes that this method provides a promising new approach for accurately measuring disk gas masses and surface densities, with potential applications to a wide range of protoplanetary disks.