Once you play with the big kahunas, your prospects will be tightly controlled and briefed by their procurement teams. Which means most of the question techniques outlined in the post will fall flat as the proc guys have read the same playbook.
This is where the side chats during coffee breaks, etc become the core. Be ready to show your software to anyone, anytime. The literal elevator pitch. Anything to outmaneuver the proc team.
Good luck :)