The estimation of rate constants for detailed molecular-level kinetic models of coal and biomass hydroprocessing is addressed. The problem is framed as, given a working molecular-level kinetic model for an existing catalyst, how many measurements must be made to have values of the rate constants for a new catalyst? The present analysis is built on an observation in the literature that the slopes of linear free energy relationships (LFERs) for a given reaction family were approximately constant upon the change in catalyst. Two subcases are considered herein: in the first, a change in catalyst leads to the same change in y intercept or "catalyst gap" for all reaction families, and in the second, the change in catalyst gap is different for each reaction family. If the catalyst gap is independent of the reaction family, only one measurement is needed to approximate all rate constants for a new catalyst. If the catalyst gap is dependent upon the reaction family, then one measurement is needed per reaction family in the system. These ideas were validated using a database for hydrocracking of alkyl-substituted biphenyl compounds on acid catalysts.