I have not yet enough experience with dead shorting so I can't answer you, but some matchers swear by it, and others tell to dead don't do it !! So,...
Regarding how to prepare the packs to zap, here's how I do it:
1. discharge to 0,9/cell at 30A on my GFX
2. put them on a tray (rayspeed, eagle, or similar) equalizing to 0,9/cell
3. then bring them near 0V on tray
4. zap with 70V on new cells, or 50V on older cells
5. let them rest (more or less 72h)
6. cycle to see how they perform
7. if not performing better I repeat the process with 70V
8. if they stay the same, buy new packs
I never disassembled my packs.
Be careful, and good luck.