rotormatic,
Of course the fuel control controls the start, otherwise we could leave it home. It would be hard for Steve76 to work the twist grip, because he has an S-76, and the engine lever is on the cockpit overhead. Not really much of a wrist action there, rotormatic.
In the specific question Steve asked, the fuel nozzel in the c30 engine is the cause. As fuel pressure rises, the spray pattern is changed by the nozzel, using a spring loaded poppet valve. This causes a pause in the temp rise, creating the double peak he noted.
The lever/twist grip has considerable adjustment range near idle, allowing the pilot to control the temperature with the lever. this sets a spring pressure on the Pc bellows in the fuel control, and that allows adjustability during the start acceleration.