Is there an independent parameter that estimates success of the global alignment?

[halil-karabacak]

Mainly the title. Since, rmse and correspondence both depend on the size of the dataset, i am not sure if i can make an assumption s.t global_rmse will be always within range 0.-2- 0.4. Therefore, I am looking & trying to find an independent parameter from the size of the dataset so that I can decide if my alignment fails or not. Thanks a lot!