[quote=@Shienvien]
	And now I'm wondering if eating, say, the hearts of two dozen unrelated twelfth-generation vampires would be somewhat cumulative, and make one closer to eleventh or lower generation vampire, or just comparable to the most powerful one of the two dozen. 
[/quote]

Sadly it would not be cumulative, no. The vampiric curse isn't something tangible wherein adding more curse results in a stronger curse (otherwise two vampires could just sit down and start drinking each others' blood to create infinite reinforcement of the curse). Rather than look at the vampiric curse as many separate entities each existing in different individuals, it would be more correct to view it as a singular entity that manifests in many individuals to a different degree. The curse can't add itself on top of itself, but a more powerful instance of the curse will replace a weaker instance of it.