Probably not the answer you are looking for but you are going to have to try it out. I too sleep very cold but I have found if my gear is rated for 30 degrees colder then I need then I normally sleep fine. As you stated some people would say your gear is overkill. Some people would say that, but not me. If it was me though I would make sure your gear works for you under controlled conditions before you take it out. Good luck.
"If animals could speak the dog would be a blundering outspoken fellow, but the cat would have the rare grace of never saying a word too much."
- Mark Twain
"FOR THE LOVE OF GOD! NO MORE WOOD!"