I'm not sure if any more development work is being done on the physics package or not. But I've gotten back to playing around with the great tetrad package you've developed.
Specfically, I'm calculating spin connections for various metrics. I've run into a few troubles, and have written a simple example showing some calculations that don't match my expectations.
This is by no means urgent, and if you are no longer developing the package, you can ignore this post.
Hopefully you can follow the code, I've commented on the issues I have, summary:
1. Checking the tetrads match the minkowski metric when contracted with the curved metric.
2. I build a tensor Gamma_mu (represents spin connection for a covariant derivative) which contains non-commuting gamma matricies (ideally dirac gamma's). I then try and contract this tensor with another non commutating tensor (dirac gamma matrix) using SumOverRepeatedIndices(). Unless I'm mistaken, this function doesn't preserve the anticommuting nature of the tensor components.