Can the spell Blood Transcription be used multiple times on the same dead caster? How many spells can you gain temporary knowledge of at once?
Blood Transcription can only be used once at a time
Same Effect with Differing Results: The same spell can sometimes produce varying effects if applied to the same recipient more than once. Usually the last spell in the series trumps the others. None of the previous spells are actually removed or dispelled, but their effects become irrelevant while the final spell in the series lasts.
Only the spell known from the last casting of Blood Transcription is 'accessible' without removing the Blood Transcription effect.
If this does not deter you, a real-world exsanguinated human provides about 10x the material component of this spell, which is as good of a starting point as your GM is likely to have for adjudicating this.