Disclosed is a method of producing a polyolefin composition comprising contacting a metal alkyl and a first olefin monomer, then adding a first co-catalyst, a second co-catalyst, a pre-catalyst, and a second olefin monomer. The method allows for the production of a series of copolymers with tunable incorporation ratios of the first olefin monomer. The method also allows for the production of polyolefins of low molecular weights and narrow molecular weight distributions.