RE: Burnt Tips
Neil, Burnt Ends, as they're called here, are my favorite, so I'll tell you what I know.
Traditionally, BE's would be made from the point of a brisket cooked whole. When the flat is done, the two are separated and the point is trimmed of excess fat and any developed bark, rerubbed and cooked another 4-6 hrs. This is how they are best, but not the only way to do it.
Burnt Ends are just cubes of cooked point (ocassionally you'll find a few chunks of flat thrown in as well). When a point is done its quite squishy, you want to cook it a little longer than that, until it starts to firm up a bit again. Not too much longer or they'll be too dry. A real (KC style anyway) end should be on the verge of dry, VERY smoky and best with a little sauce (spicy for me).
You can separate the flat and point before you begin to cook and get a decent end, but the very best stuff will come from a resmoked point.
Best of luck!!