KT, those lat raises are a killer! They, along with moves like flyes and reverse flyes can be done with very minimal weight - it's actually better than using too much. I've found that by using a lighter weight and emphazing the eccentric (the negative portion of the move) and squeeing when you're at the peak you can get a more intense 'burn'. Form is more important than poundage At one point I actually had to remove all plates from my adjustable dumb bells and do them with only the bar (3 lbs).

HTH
Nat