I have a html/css website and I am trying to change hosting. right now it's an add-on domain in shared hosting I will be moving it to another host, again as an add-on domain I am trying to figure out what's the best way of doing this so downtime is minimized. do I change dns settings at like 10 pm when traffic is down, then in the morning transfer the files? or do I transfer the files first, then do the dns change? or ???