The $450 asking price suggests this kit is heavily used and no doubt worn, with no guarantee it is operating reliability (very especially after coming from professional use).
I would stick to 35mm and continue actively looking for a MF kit in very good condition with a reasonable amount of life remaining, so that you are not left with a bitter taste getting a worn, sub-standard system that will require you to outlay maybe twice or three times as much in repairs and overhauls. If it sounds too good to be true, no doubt it isn't. I really do not think it is worth the risk.