Hi, regarding your maxdim question, the reason it saturates to 110 is probably because you also have set a cutoff. The cutoff will eventually limit the actual maxdim reached. They work together to determine the actual maxdim reached. What cutoff do you have set?
Regarding the other two questions about PBC and finite temperature, could you please post a new question or questions about these? It is a longer conversation.
Briefly: you can use a PBC Hamiltonian on a regular (OBC) MPS, though the cost can be rather high. It’s usually not worth it unless you have a good reason. For finite temperature there are multiple algorithms and which one you use depends on what temperature range you need, how entangled the system, and how much coding you want to do. It’s a whole subject unto itself.