[Phubar]

As far as a mini UDS goes...mount the upper grate as high as possible (just below the rim of the drum) if you're gonna use a Weber lid.
The lower grate should be low enough to put a whole chicken (unspatchcocked) between the 2 grates.
Make your charcoal basket not too tall but wide.
If you want a diPhuser...mount it in.
A mini isn't much of a difference in build compaired to the 55 gallon UDS.
I hope this will helps you a bit and if not others will chime in.