Just started using this lump from Sam's Club called "The Good Charcoal Company". Lump pieces are on the smaller side, but it seems to last as long as Jealous Devil. Price is about $12 for a 15.4lb bag. Only done 2 cooks with it, but impressed so far.
I accidently did this last cook. There was a decent amount of B&B lump left over in my WSM, so I added B&B briquettes to fill in the gaps. I felt I got the consistent temps of briquettes and a bit of the lump flavor I like.
I brush the grate before and after every cook. Once in a while I'll lightly scrape the inside of the lid and bowl to get the flaking buildup off and then hit the outside with simple green to shine her up.
Wow, glad I found this post. I just scored an 18" WSM locally for $100 and have the same issue. If you move the grate completely to one side, it will fall off. This does not happen on my 22" WSM. I'm probably going to add a few washers like recommended here and see if that fixes it.
My WSM 22 is weird, I have to fiddle with vents for the first 3 hours to maintain temps, but after the 3 hour mark, the temp hardly moves, usually likes to settle around 270-280 and wont move from there. This is with an empty foil wrapped water pan.
I bury wood chunks in my kettle and WSM, great results every time. I will say I've never used 8 chunks, more like 2-3 for chicken, 3-4 for ribs, 4-5 for pork butts and brisket.
Here's a video comparing chunks on top vs buried.