This is a question for your Hydrocracker licensor and catalyst vendor. The sources of feed for the Hydrocracker will influence the yield profile. Gas oil from the Delayed Coker will require more hydrogen than the same boiling range gas oil from the Vacuum unit producing the same products. That will require more severe operating conditions for the Coker gas oil than for straight run gas oil. Operating pressure and hydrogen make up rate as well as recycle hydrogen purity all influence the outcome, as I understand it. Hydrocracker yield prediction is normally left to the licensor.