While I don't believe Nichols and McVeigh acted alone ( amply demonstrated by my site,
http://www.whoisjohndoe2.com ), I do believe the April 19 date was chosen for Waco and no other reason. There is an overwhelming mountain of evidence that Waco, and anger over Waco, form a continuous thread throughout the lives of Nichols and McVeigh. I don't see a compelling reason to look further for that particular aspect of the story.
jmb