S&T Compensation Question

Came across a position at a reputable firm in my area for a Junior Equity Trader role. This firm makes a market in over 250+ companies and pays Institutional Sales, Traders and Research Analysts on commission and not a salary. I know the guys there do pretty well (by my standards) and am curious if anyone on here could provide some insight as to what you are typically paid commission on, and how much one would generally expect to make in their first couple years as a Junior Trader and Trader with this comp structure.

Thanks in advance!