The people spreading your theory are too corny for me and seem to have an agenda of their own.
Witness General Partin who lent his name to the Waco trials that involved Ramsey Clark and Kirk Lyons, whom McVeigh called the day before the OKC bombing.(!!!) (Lyons is Andre Strassmeir's attorney.)
By shifting focus to forensic questions about the bomb and shadowy government conspiracies, general government arrogance/incompetence is overlooked.
You believe they LOST a huge ryder truck? They knew the date of the attack and the building, why weren't undercover ATF agents surveiling every aspect of the murrah bldg? If a ryder truck pulled up in front, couldn't they have swooped in immediately, arrested the drivers and defused the bomb?
Good point, but that wouldn't prove or disprove this story. The government would lie and cover-up evidence to cover their arrogance/incompetence from discovery.