You should definitely use Spirit Bomb instead of Blade Turning. Aside from that 25H ToT should probably not be difficult - you can spec havoc for most of the bosses at your ilevel.
You can start heroic HFC, but clearing it in its entirety will probably need a bit more gear (mostly for Kilrogg) unless you are very confident in your play.
If you want a fun challenge though I would definitely suggest you try it now, as it gets trivial very very quickly once you get 900+ gear.
(You need Mirror of the Blademaster for Archimonde by the way if you are going to attempt it now. And I'm not sure if they fixed Zakuun resets like they did for Gorefiend).