I'm not disagreeing with other answers. If you can get by with less, do it. But I also feel like 30 lbs. is a reasonable amount of weight to be carried of one rack. So see what you can leave behind, but I would say also see what you can do about losing a rack.

I agree that multiple racks give you more carrying options, which is nice, but if you objective is to keep it light, I don't think I would spread < 30 lbs. of gear over 2 racks.