so you'll pardon me if I put more weight on my opinion than yours.

And you must pardon me if I find that:

• Your reference work pertains to an entirely different problem - one of interstellar planetary destruction.
• Your reference work pertains to killing a population not destroying the planet itself.
• The limiting factor that you appeal to is the lack of fissile material. This is an artifact of the tactic you have adopted of making many moderately sized nukes. If someone was optimizing the total amount of explosion they could make from a given amount of fission material they quite obviously would change the design. For example they would include a third stage of fusion fuel. Most bombs that been constructed thus far (with the hypothesized exception of Tsar Bomba) have not bothered to do so because, well, what would be the point?
• You haven't even seemed to acknowledge that there is a problem making your projectile effectively destroy the earth when it has been accelerated across the surface of the earth and so is pointing in totally the wrong direction.

Whatever mass of theoretical expertise you may have behind you, you most decidedly haven't applied it coherently here. To the extent that if you had just made an assertion and appealed to your own authority I may have believed you but given that you explained details that are clearly wrong I have to dismiss it out of hand.