RSS Pinging - How much? Custom vs. Already made? Same URLS vs. Multi-Combined? Same Niche?

Hey all,

Just a quick question regarding RSS pinging. I'd like to ping my various backlinks and looking for a safe amount to do + have some other questions regarding them. If anyone can contribute that would be great! The reason for so many questions is because I've heard of people who ping too much and end up getting sandboxed from their massive amounts of links getting indexed faster and not being able to maintain that.

1.) How many links should I put in per RSS ping?

2.) Should I create my own RSS feeds with only my links? Or ping the entire feed. (For example: If I have 100 blog posts on various blogs, should I ping the entire feed from each blog, or create my own RSS feed with only my links in it?)

If I should create my own, are there any tools to just pour the links into and have it ping them? Should I include ALL types of links including social bookmarks, web 2.0s and forum profiles etc?

3.) May sound like a stupid question, but should I create my own custom ones only pointing to the same domain or is it okay to mix?

4.) Does it matter if I ping the same niche together? Could I put in 1000 links in a niche like perfume and 1000 in from cars and 1000 in from SEO?

Any input, experiences, horror stories and success stories would be appreciated!