I have 4 kids and while they are still young, (5,7, 10, 13) we all manage to fit in the nest without too much trouble. If full size, I am not sure you could really fit 5 in the nest, but without it (only using the outer) I suspect even 5 full size sleepers should fit, but still a bit tight.
I was using two two mans, or a two man and 4 man coleman family tent, and when the wind caved the coleman tent, I dug around and found the Golite SL 5.
I have been very happy thus far, and the weight savings was HUGE compared to what I was using.
At this point, it is more important that my kids enjoy the time, and I end up carrying a bit more than all go ultra light just yet :)