Best way to truncate feed

[tamjl]

I've been using WordPress for a decade but have never used feed excerpt or summary. Now I may do so and need some guidance on the proper way to do this.

I want to be able to:

• Preserve images in the excerpt or summary
• Preserve formatting (paragraph breaks, etc) in the excerpt or summary
• Ensure that only the excerpt or summary shows in the RSS feed
• Have a "read more" link that's inserted automatically (ideal) or manually (ok)

I am aware of the full text/summary option in Settings > Reading and I am aware of the Excerpt box option on the post's admin page. I use Genesis and Feedburner and I use Aweber to distribute the feed to email subscribers.

Can someone give me guidance on the proper settings to use to achieve the four requirements on my list? Thanks!