Chins
Is there a reason for chins, as opposed to pullups? Assuming there isn't a big difference. I couldn't agree more about the lat builder comment. I started doing pullups in about March/April this year. I've had more growth since March with pullups than I've had in 7 years from pulldowns. And I've only been onto weighted pullups for a couple of weeks.
Deadlifting (back on topic)
At any weight is it a good idea to go past 5-6 reps? Your form inevitably begins to slip and the issues with that only grows as the weight increases.