Its Cherry Wood
I place just enough over the fire to ignite and its burns back off of the fire pot and smolder's and makes smoke.
I have the temp set to around 200 so the foundry flame subsides and the smoldering wood doesn't create enough heat to interfere with the temp probe and create a false heat that the system can't fix by shutting down the hopper. (I have made many test runs to ensure this)
I took a simply self tapping sheet metal screw with a 5/16th hex head, added a washer and drilled it down to the top of the SS that incorporates the firepot assembly. there is ample room for the screw and I let it hang over the firepot around 1/2 and inch just so when the wood lights it won't have a chunk of char or ash drop in the firepot and create ash that would smother the fire. (Once again I have tested that to ensure the integrity)
I use one chunk that size and it lasts about 2 1/2 hours in which I think provides ample smoke and color for my Big Meats since it is Cherry wood. If it was something else I might add another chunk after that one was burned out.
PS: Design credit goes to Scottie Johnson (Cancer Sucks BBQ Team)