This is in response to Berley Firmin's question.  Here is the system
I developed thirty years ago.

First I have three questions.  Why did you remove the stack if you
did not recover the pneumatics?  The valves can all be removed without
removing the stack.  Second, are you sure this unusual yellow cloth
is what you really want to put back into the piano?  Have you bench
checked the valves, particularly the primaries?  You want them perfect
before retubing the stack.

To easily install the stack, you will need two threaded rods about
12 to 15 inches long, two fender washers that will fit on the rods,
and two thumbscrews, one for each rod.  You will also need a vacuum
source with two outlets or a "Y" connection.

The rods must match the diameter and thread of the Ampico stack
mounting screws.  Attach the rods to the piano in the mounting
brackets.  The two rods will now be pointing at the floor.  Place
the stack, without its mounting screws, directly below the two rods.
Raise the stack so that the rods go through the stack mounting screw
holes.  Place a washer and thumbscrew on each rod, beneath the stack,
which will hold the stack off the floor.

Gently raise the stack until the push rods just start to touch the
tubing harness mounting under the key bed.  Adjust the thumb screws
to hold the stack in this position.

Attach a vacuum source to each end of the stack.  The pneumatics will
all attempt to collapse.  Thread each push rod in its proper spot.
This is done by holding each pneumatic open, against the vacuum, and
then allow the vacuum to raise the push rods in their proper location.
With the vacuum still on, raise the stack gently until the push rods
start to contact the guide holes.  Adjust the thumbscrews to hold the
stack in this position.

Once more position each pneumatic so that the vacuum will lift the
push rods into their corresponding holes.  Repeat as necessary, raising
gently the stack and holding it with the thumbscrews until the stack
is all the way up.  Turn off the vacuum source.  Carefully brace the
bottom of the stack and remove one threaded rod.  Replace it with the
stack screw.  Repeat the process with the remaining threaded rod.

This whole process can be accomplished in 15 minutes.  A word of
caution:  Each time the stack is repositioned higher, make sure
that each push rod is in its proper location and free to move higher.
The push rods do not engage the overhead obstacles simultaneously.
Breaking a pneumatic is a real possibility if caution is not exercised.
Frequently check the pneumatics to make sure they are all closed the
same amount.  Any pneumatic that is open signals that the corresponding
push rod is binding on something.

Good Luck!

Bob Taylor