You need to connect the main outputs of the MG124C to the inputs of the Finalizer using standard unbalanced quarter-inch jack leads, and the outputs of the Finalizer to inputs of your recorder using quarter-inch jack-to-phono (RCA) leads. Seeing as the inputs to the recorder are on unbalanced RCA sockets, there is no point in going balanced, you may as well go for unbalanced operation throughout, if the leads are short and not over about 3 meters it shouldn't matter. Seeing as the Finalizer is a mastering tool/compressor etc it needs to be inserted directly across the whole signal path as mentioned above, you do not want to have any part of the signal "unprocessed"
PP