Spacing out your tweets is a great way to avoid flooding your Twitter feed. Adding retweets to your queue within Buffer ensures you're still providing great content to your followers, but within your preset schedule, thus avoiding overwhelming them. To schedule retweets, you will need to have the Buffer browser extension installed.
Find a tweet you'd like to retweet and click the Buffer icon.
The composer will open on the page, allowing you to add a comment (optional) and then add the post to your queue. Guidance on scheduling options can be found here.