When to close the lid?

Shouldnt matter a whole lot. Just make sure you have a full load of lump, the egg is relatively clean of ash, etc and let er rip.

Here is how I do it for any temp really, the best way to get the lump going, at least using starter cubes, which is all I have ever used, is to place them in three places in your lump, 10-2-6, push them down into the lump a little and light. I am cooking on a large, I cut the cubes in half diagonally, so I am using three triangles, 1 1/2 cubes.
I let them burn for no more than a minute or so before closing the dome, Bottom vent wide open, top vent not in place. You will get a little surge of heat from the cubes, then things will settle down as the lump ignites and the cubes die out. After a few minutes things will happen quickly as the lump catches and you just have to watch your temp and slow it down on the way up. It takes a little practise and patience, but it works
Sorry this is so wordy, but that's how I do it, and I wanted to be thurough :laugh:

Capt Frank
Homosassa, FL

Unlike the previous respondents, I let it burn for awhile with the top open. I feel it engages more charcoal that way. I typically do this until the starters have all burned up. I do this for ordinary temp cooks too, not just high heat.

Then i close the dome and the chimney effect kicks in.