Any build up of carbon in the bores will soon be burnt off when you give the engine some stick / load.
If your glow plugs are functioning correctly, then there is no need to do any more than turn the key, wait for the coil light to go out and start the engine.
I do think you're worrying a little too much about this
If your glow plugs are functioning correctly, then there is no need to do any more than turn the key, wait for the coil light to go out and start the engine.
I do think you're worrying a little too much about this