Since you have a 166 already, it seems your issue with getting a higher score might be fixing small issues like getting better at logical reasoning or improving at specific question types. It might be better to focus on things like that, rather than spending more time doing practice tests. I personally tried doing more than one a week, and it really burnt me out. I suggest focusing on improving your weaknesses with strategic drills while PT-ing once a week, maybe twice if you have a very free schedule so that you can stay energized!