Well I am no battery expert, but I will just let you know of my experience with storing batteries. Now, the batteries in question are 1700 scrc's (the black ones) so i dont know how well this will apply. I had quit the hobby about 6-7 years ago but never sold any of my stuff. Just recently (about 5 months ago) I dusted everything off and started up again. I had left my batteries in my basement in a box. They all had been drained to 0v per cell (i had a homemade pin-board with toaster wire at the time). Now when i pulled out the batteries some 7 years later, I was very curious as to how they would hold up. So I cycled each pack once and then took them racing. Surprisingly they hold up for 4mins in mod/foam sedan (unfortunately the race is 5mins) and 5min in rubber/stock sedan. Now I was curious to see how much the cells had degraded since i purchased them eons ago. Since I 'matched' my packs with a ce linear turbocharger (the little white one) and I luckly still had the stickers on the cells that i had made, I could once again use the same charger and match them again. after a laborious week of babysitting the charger and cells, the results are in. it appears the each cell on average dropped 30 seconds since i bought them 7 years ago. now it is important to note that both cycle specs(7 years ago and now) were only at a 3 amp charge and a 10 amp discharge, because thats all the charger would do. But alas just last week, my old cells started venting on me so I decided to retire them to practice packs and order some new ones.
I hope this sheds some light for your storage question. I know most people just say 'do this' and not know why. I just wanted to let people know what I had experienced and you can draw your own conclusions.