Connecting Big E to existing chimney - What Pieces are needed?

[Extremesolo]

Since we are moving in the spring I want to vent my new Big E directly into my existing chimney without a liner. If it doesn't work properly then I will install a liner. I know the application at the new huse will probably be different and don't want to waste the money on a temporary installation. The existing chimney has a 7" clay pipe through the wall that my exhaust will need to vent through. I will try to attach a few pictures so you can see what the installation will look like. The stove outlet is 18" below the chimney opening. Will I want to run 3" or 4" pipe? I will at a minimum have to 90 it up and 90 it over to where the chimney opening is located and then another 90 if I should turn it up inside the chimney. Where should I locate a T (directly behind the stove, inside the chimney) and also should I turn a 90 up inside the chimney or is that not necessary? What should I use to seal the larger 7" opening in the chimney since a 3 or 4" pipe will be run through it? Where is a good place to buy the pipe and other materials that I will need? Is Lowes or Home Depot acceptable or should I look elsewhere? I just carried the stove downstairs last week and 2 tons of pellets on Saturday so since it is getting cold now, I would like to get this thing fired up. Please bear with me as I am new to pellet stoves.