Multipath transport communication solutions gain traction in the communication networks industry. In particular, Multipath Transport Control Protocol (MPTCP) emerges as a viable transport protocol, as it is conceived as a TCP extension, incrementally deployable in the legacy Internet. MPTCP might improve throughput provided that the TCP buffers are big enough, otherwise the opposite may happen. When facing a situation with many paths available, it might be efficient for MPTCP not to use all of them to prevent throughput degradation because of head-of-line blocking. How many paths should be used remains an open question. Depending on the use case, it may be important to keep a path alive for confidentiality reasons or because of the financial cost associated with transmitting over the other paths. We document the MPTCP-NUMERICS tool we developed to manage MPTCP buffers. MPTCP-NUMERICS tries to take into account the MPTCP flow control constraints as well as policy-based constraints in order to answer such questions.