Strategist role at an agency broker

I recently interviewed with the owner of an agency broker here in Chicago. No one has heard of them, and they are fairly new. Basically, they execute trades for large institutional clients, including janus, PIMCO, SAC, and others. They are looking to expand into other business areas and want to bring me onboard as a strategist; in this capacity, I will formulate trading ideas for the clients.

I am gonna go in for another meeting next week to meet the other guys, but there's a very good chance I'm going to get an offer. The problem is that the owner said explicitly that compensation will be "mostly incentive based." I take this to mean that the base salary will be rather quite low, worse than what I'm making now.

Question: What is the potential upside to such a job, if any? Does working with major institutional clients have any advantages? My friend knows this guy quite well and is urging me to take it even if the base is not what I want. He said the upside could be quite huge. But of course, everybody says that, so I take it with a grain of salt.