A method for forming a thermally conductive thermal radical cure silicone composition comprising a clustered functional polyorganopolysiloxane; a silicone reactive diluent; a filler comprising a thermally conductive filler, (III') a filler treating agent, and a radical initiator, the method comprising: providing a clustered functional polyorganosiloxane that comprises the reaction product of a reaction of: a) a polyorganosiloxane having an average, per molecule, of at least 2 aliphatically unsaturated organic groups, b) a polyorganohydrogensiloxane having an average, per molecule, of 4 to 15 silicon atoms and at least 4 silicon bonded hydrogen atoms per aliphatically unsaturated organic group in component a), c) a reactive species having, per molecule at least one aliphatically unsaturated organic group and one or more curable groups selected from acrylate groups and methacrylate groups, and in the presence of d) a hydrosilylation catalyst and e) an isomer reducing agent, wherein the isomer reducing agent e) comprises a carboxylic silyl ester or 2,6-Di-tert-butyl-4-(dimethylaminomethyl)phenol, forming a mixture by mixing the filler comprising the thermally conductive filler, the filler treating agent (III'), and at least one of the silicone reactive diluent and the clustered functional polyorganosiloxane; heating the mixture to a temperature from 50°C to 110°C to treat the thermally conductive filler with the filler treating agent (III') in the presence of the at least one of the silicone reactive diluent and the clustered functional polyorganosiloxane; introducing either the silicone reactive diluent or the clustered functional polyorganosiloxane to the mixture such that the mixture includes both the silicone reactive diluent and the clustered functional polyorganosiloxane when the mixture of Step does not include both the silicone reactive diluent and the clustered functional polyorganosiloxane; and then cooling the mixture to 30°C or less and then blending a radical initiator with the mixture to form a thermally conductive thermal radical cure silicone composition. providing a clustered functional polyorganosiloxane that comprises the reaction product of a reaction of: a) a polyorganosiloxane having an average, per molecule, of at least 2 aliphatically unsaturated organic groups, b) a polyorganohydrogensiloxane having an average, per molecule, of 4 to 15 silicon atoms and at least 4 silicon bonded hydrogen atoms per aliphatically unsaturated organic group in component a), c) a reactive species having, per molecule at least one aliphatically unsaturated organic group and one or more curable groups selected from acrylate groups and methacrylate groups, and in the presence of d) a hydrosilylation catalyst and e) an isomer reducing agent, wherein the isomer reducing agent e) comprises a carboxylic silyl ester or 2,6-Di-tert-butyl-4-(dimethylaminomethyl)phenol, a) a polyorganosiloxane having an average, per molecule, of at least 2 aliphatically unsaturated organic groups, b) a polyorganohydrogensiloxane having an average, per molecule, of 4 to 15 silicon atoms and at least 4 silicon bonded hydrogen atoms per aliphatically unsaturated organic group in component a), c) a reactive species having, per molecule at least one aliphatically unsaturated organic group and one or more curable groups selected from acrylate groups and methacrylate groups, and forming a mixture by mixing the filler comprising the thermally conductive filler, the filler treating agent (III'), and at least one of the silicone reactive diluent and the clustered functional polyorganosiloxane; heating the mixture to a temperature from 50°C to 110°C to treat the thermally conductive filler with the filler treating agent (III') in the presence of the at least one of the silicone reactive diluent and the clustered functional polyorganosiloxane; introducing either the silicone reactive diluent or the clustered functional polyorganosiloxane to the mixture such that the mixture includes both the silicone reactive diluent and the clustered functional polyorganosiloxane when the mixture of Step does not include both the silicone reactive diluent and the clustered functional polyorganosiloxane; and then cooling the mixture to 30°C or less and then blending a radical initiator with the mixture to form a thermally conductive thermal radical cure silicone composition.