[swift] Adding disks - one by one or all lightly weighted?

Hi, We are wanting to increase the number of disks in each of our storage nodes - from 4 to 12. I'm wondering whether it is better to: 1/ Add 1st new disk (with a reduced weight)...increase the weight until full, then repeat for next disk etc 2/ Add 'em all with a (much i.e 1/8 of that in 1/ ) reduced weight...increase the weights until done Thoughts? regards Mark