The key to influence lies in the selling tools you use. Don't expect your champion to be able to digest all of your product's key benefits and produce an internal presentation that recommends your solution; do it for them.
Two standard documents that every sales person should have in their arsenal is a sample Project Plan (with a matching, simple powerpoint deck) and a "Top 30 customer requirements" document. When you find an opportunity it is important to set the ground rules for how the final solution will be chosen and without these documents you are leaving it up to the committee members to "stray" toward other options. Use the fact that time is scarce for everyone. If you can help write the internal documents that your champion will need for the project, you will have a good chance of being the chosen vendor.
Next time you engage a new prospect, simply ask them "What type of planning documents will you need to create to move this project forward in your organization?" Then proceed to put that document together for them in electronic form. It is best to deliver it in person to ensure it will be used, avoid email if possible. Your chances of winning the deal will dramatically improve.