I agree that 3-4 days is plenty of notice for every exchange to get the new wallet, test it on their system, and get up and running. Definitely want to avoid having to undo the hard fork. Whatever you decide we, as a community, will support you. We all see great potential for mainstream adoption. I assume (gets me in to trouble often) that one of the builds will contain the switch to POS at a later block? That will also be need for longevity and to get some people to use/stash coins in wallet and keep the network running at a fast rate as mining slows down.  I am sure if it isn't added now that it can easily be implemented down the road. Anywhere from 5-15% stake option would be a nice incentive to get coins off the exchanges. Just my thoughts. Great job so far, Devs!