The MGBS-TGAL combination of the J70 criticality modules was validated for Mark 16 lattices by H. K. Clark as reported in DPST-83-1025. Unfortunately, the records of the calculations reported can not be retrieved and the descriptions of the modeling used are not fully provided in DPST-83-1025. The report does not describe in detail how to model the experiments and how to set up the input. The computer output for the cases reported in the memorandum can not be located in files. The MGBS-TGAL calculations reported in DPST-83-1025 have been independently reperformed to provide retrievable record copies of the calculations, to provide a detailed description and discussion of the methodology used, and to serve as a training exercise for a novice criticality safety engineer. The current results reproduce Clark`s reported results to within about 0.01% or better. A procedure to perform these and similar calculations is given in this report, with explanation of the methodology choices provided. Copies of the computer output have been made via microfiche and will be maintained in APG files.