I think you mean non-replicable MSA.
According to MSA 3rd, it requires studies on Discrimination, Accuracy (Bias, Linearity) and Precision (GRR) for a variable gage system to make the system is suitable for a characteristic.
Since, Accuracy and Precision studies are based on repeatable measuring data, it is very difficult to conduct such studies on non-replicable system.
I always ignore Accuracy Study.
I focus on Precision (GRR) and try my best for that. Starting with Homo-genius and Hetero-genius assumption. Then, ANOVA GRR on the data.