I am not an expert...but I like trying. :P
I used to Dual-wield, and would not advise going into it for serious tanking; I had serious issues with threat - of course I was a worse tank back then than I am now, not that I am great now.
I don't want to sound rude, but...I have no idea about your stats. If you don't want your character's name revealed, you can export your character data to some site and post that link, while talents can be exported via WoWHead or MMO-Champion.
Trying to hit the hit-cap for Frost-d/w is impossible, or you'd be giving up practically every other stay to gem for hit: 27% is the d/w cap. The expertise "hard cap" (parry) is 15%/60 and is not too easy; at least 27-30 expertise is what you should aim for.
Talent Calculator - World of Warcraft - I wasn't completely decided on whether to go for Deathchill or Chill of the Grave...for a while.
Rotations are harder for me to think of, since I d/w-ed at a time when I was...more prone to facerolling? I tried to come up with some "rough" ones.
Double Disease, Single Target
IT -> PS -> BS -> BS -> BS -> BS -> FS
Single Disease, Multiple Targets (Need not glyph HB for this)
D&D -> IT -> Pt -> BB -> FS
Double Disease, Multiple Targets (Glyphed HB)
HB -> PS -> Pt -> BB -> BB -> FS
I know the rotations don't use all the runes and seem crude, even inefficient - and they are so! However, they are the best my sleep-deprived, fuel-starved mind could come up with. I apologize...
I have other choices for glyphs - which would have affected the rotations.
Glyph of Icy Touch and Glyph of Rune Strike.
The state I am in right now, I'd rather not write something silly, irrelevant, or worse, wrong. I hope this post has been of some value, at least. :-)