Great question Al and always a subject for discussion on a fireplace install of a stove! the subject matter is here for you and many people have done this many ways...
On a Crane 404 install to an existing fireplace (which is exactly what the 404 was designed for) you dont really have to use a "T" because of the removable baffle. I will give you one thread I can grab easy because i wrote it that you will like reading Removing a Built in damper from fireplace
, but their are lots more im sure you could search for as well using the search box in upper right corner of this page^^^ (type things like Fireplace Blocker, Damper Removal, Fireplace Install, etc.)
I personally like to get the portion of pipe going up the chimney past the smoke shelf area (preferably into the flue or smaller bricked area of the main chimney run), it does not much matter if you blocker board/sheet metal is used in the smoke shelf/damper area OR on the face opening of the fireplace itself (in my case i needed the stove to sit a couple inches inside the fireplace opening to allow my hearth to remain untouched with no extensions or loss of sq' liv area). The comment of using fireproof insulation around the "thru pipe" is smart in either case (my own blocker plate is actually cemented in place as a permanent attachment to the chimney and the 6 inch thru pipe cut was so tight and accurate i did not bother stuffing insulation into a gap that was non-exsistant (I should and could put a bead of furnace cement around the seam... maybe ill get to it someday
) expansion & contraction will make that seam fail every couple years anyways so i just did not bother because i got the pipe to fit so snug.
i have some other threads showing my install im sure someplace in the Crane sections "fireplace reface" maybe? their are also brackets that can be bought or made that hold a pipe centered in a flue as well, but my pipe goes at a slight angle about a foot into the terra cotta liner and is secured by the tight 6 inch hole cut into the cemented rock board and secured to the flu collar on the 404 itself (it wont be touched again unless i replace the black pipe in 10 or 20 years
). Some folks screw the pipe to the stoves flu collar while others take a large super quality hose clamp and secure it that way (your going to find the pipe is SO snug once you get it to slide onto the flu collar that you would mystified how it could EVER move (even with no screws or pipe clamp)
I use a blower at times on my stove and having the rear of the stoves a few inches into the fireplace opening keeps any noise the blower makes "inside" the firebox and not in my living room. If your blocker plate is on the face of the fireplace your draw comes all the way down inside the firebox of the fireplace (which is more often than not the area you may have loose brick/mortar as well as ash dump, etc.... all places of potential loss of draw/draft into the stove). some advantages of blocking the fireplace opening is that your not heating the firebox area (i think the heated pipe makes up for any of that though) and if your firebox is much larger than the stove you may not want to see inside the fireplace if its unsightly? also one last thing you want to keep in your minds eye while making these decisions is converting back to a conventional fireplace someday upon resale or whatever (i suggest you keep your removed damper plate up inside the smoke shelf! this is the first place folks will look for it long after your gone
hope this helps give you some good food for thought... we look forward to your photo's and threads as your moving along....