When I bulit my new barrel in '13, I used the tutorial from this site. But, I still wanted to be able to hang tritip, chicken, etc. So I drilled holes just under the top rim. which double as exhaust and rod holders. Ceramic magnets cover them at the end of the cook.
I've never used a diffuser plate when cooking meat, the more drippings vaporized by the coals, the better. But, when using the grates, I do use a pizza stone under pans of beans or vegetables.
This was the debut of the new UDS, cooking hanging halved chicken, for about 40 of my fishing buddies.
But, it's really nice to have a grate, we do a lot of fishing.
And our current new favorite, corned beef with smoked cabbage. It's not just for St. Pat's day anymore!
Lastly, I have an extra barrel on hand, and want to add a removable section, that will stack on top. Room for 3-4 more racks, and a rotisserie. Seems somewhere on this site, I'd seen it, Just haven't found it yet.