Lots of stuff written on this in the past. It’s a pretty common pattern like using a template in Microsoft Word. Here are just a couple from searching.
Probably not. A lot of folks, myself included, like the ability to start a sequence using a profile, then have the ability to modify that sequence for special circumstances without actually altering the equipment profile. If you want to update your profile to reflect recent changes to your sequence we have provided a very easy and convenient feature to do this on the file menu.
http://mainsequencesoftware.com/Content/SGPHelp/SaveSequenceasProfile.html