Oh boy, you have a tough assignment. I know there's been talk that you should do a citizens' assembly, and I know that's not going to happen.
On the other hand, they're well written up. What's interesting about the B.C. citizens' assembly and the Ontario one is that they really were genuine efforts to get a cross-section of people in their respective provinces, most of whom had never even thought about electoral reform, to apply their minds to it for a month or so and to just keep on and think about it, and they came out very much for a proportional representation change: STV in B.C. and MMP in Ontario.
You haven't had one of these assemblies, but to me these are very impressive. All you can do, though, when people come before you and proclaim that this or that will happen, is to keep asking them for evidence. I think the more evidence-driven you are, the stronger evidence you'll have for a recommendation.