Backlinking HTTP vs HTTPS

So with the latest announcement that Google is boosting SSL-encrypted websites, I am pondering the following scenario:

All of my backlinks have been built to my domain and inner pages using HTTP. For example:

HTTP://www.domain.com
HTTP://www.domain.com/page-1

If I was to get a SSL certificate for my domain, my understanding is that my pages would change from HTTP to HTTPS. For example:

HTTP://www.domain.com
HTTP://www.domain.com/page-1

1. How would this change impact the juice flowing from backlinks built to HTTP://www.domain.com?

2. Do I need to 301 redirect from http to https?

My thinking with this announcement is that this won't provide much of a ranking boost... if they're making it this obvious, it's likely to be quite low on their "list of 200" factors they use.
With this site, I wouldn't go through the trouble, I say leave it as is and keep building to the HTTP. Any new sites you might want to buy the SSL cert to get that mini-boost.