Cost of redirect and site domain switch? Good Practice / Bad Practice / Terrible Practice

So, I need to change from somedomain.com to somenewdomain.com I was thinking of doing this 1) create an alias to the site somenewdomain.com to point to current server 2) run permanent 301 redirect from somedomain.com to somenewdomain.com I was thinking this was a clean safe way to do it so we dont have to run a global find replace. Concerns might be but, I don't know for sure? 1) SEO 2) processing / time / cost for the 301 redirect on any old somedomain.comrequests What do you guys think? Thanks, T