Are you aware that workshop manual (downloadable on Engenia's Benelli Tornado Novocentro Tre) has the specifics for each screw?648 and 243 or do you recommend others/better?
i.e. Page 159: "Block the clutch bell unit with the specific instrument. Screw and tighten the nut with loctite. Worm drive: 80 N.M 8 Kgm Loctite: 648® "