Fascinating mods, there! I haven't used my Brinkmann SnP since I built my drum...and saying built is taking liberties with the word! As far as the drum goes, I drilled 16 holes...wait, 21 if you count the handle and the temp probe holes...installed a handle and 4 bolts. oooh. The firebox isn't much more sophisticated, just 2X4 piece of expanded #9 X 3/4" bolted in a circle, bolted to a charcoal grate and a pizza pan.
Anyway, you're probably going to be eating in just a little while. Congrats...looks awesome!