tall closet inset doors

[vaking]

The boss ordered a new closet to be built. It will be a built-in with an opening 36" wide and all the way to the 8'- ceiling (minus moldings). I plan to build inset doors with blum hinges. In order to make doors lighter I plan to build shaker style doors with 1/4" plywood instead of panels.
I will end up with 2 doors 92" long and 18" wide each. The plan I drew calls for 3 plywood panels in each door, 3"-wide styles and rails gradually increasing towards bottom. The top rail will be 3" wide, then 4", 5" and 6" rail at the bottom. Panels will also be increasing in length towards bottom, something like 22", 24" and 27".
Questions:
1). How much clearance do I need to leave for inset doors? I always tend to try to make things too perfect. I know if I make doors exactly 18" wide - doors will not close but I want the gap to be as small as possible.
2). I figured I would need 4 hinges for each door. I plan to install a hinge against a center of each rail. Did I make a mistake in the design?
3) Few days ago I came accross an HD clearance of select/premium grade pine and I stacked up on it. I have more than enough for this project. Do you think pine will work for 92" long doors?

I have never seen doors so tall but this is boss's order. BTW - it will all be painted. The built-in is supposed to "blend with the wall".

[cabinetman]

Your plan sounds OK. They won't be that heavy. Poplar would be a better choice. If you could keep a minimum of 3/32" to 1/8" all around and in the middle, that would look fine.

Actually for those sizes, overlay doors would be my choice.
.

[pecker]

I built some tall doors from lyptus and mahogany ply. I took every precaution, but after hanging they all bowed a small amount. Since they are full overlay with face frames it's no too noticeable.

But 2 inset doors with different warps in them may not look too good where they are suppose to meet in the middle.

I probably would just buy a manufactured 36" door and close in the top area like a conventional built-in closet.