One of the reasons you may have difficulty in your burn may be because lump burns much cleaner and hotter.
I have seen people make a charcoal basket in a maze manner to use lump in the minion manner of controlling their burn.
Here is a picture from another post from "KotaChuk678" who used expanded metal for such a project. This is his picture from another thread, NOT MINE.
KotaChuk678's Basket for Lump Charcoal
