I'm quite sure Les was in charge of the football side of things under the Cortese regime. Whilst Nicola took the glory and indeed probably did the final negotiations in a lot of stuff you have to credit Les with the groundwork and the detail.
Cortese did well in hiring a good egg in Les and backing him to build an infrastructure. To say any more than that is down to Cortese is fantasy. Les has been more public under Krueger, but I suspect that he's pulling the strings almost the same.