the torque wrench is really the best 90-110 Nm and it is without risk estimated that the 100 Nm per 25 cm hand lever so 40 kg (half body weight) but it depends more on the order (first upper, then lower, opposite crosswise) and mainly on the jack, just tighten it firmly, then lower the jack to the ground and only tighten fully on the ground (calmly step)