What I have learned since the original install?

• When cutting the investigation hole (to determine there are no obstructions) use a reciprocating saw but hold the blade at an angle towards the center so if you had to replace the piece you just cut out, it would wedge back into place easily with a little drywall mud.
• Raise the Retro-Fit box about 1/4" above the floor, this will give you some extra room to negotiate the tuck-in operation later. 
• The current design now has just 2 mounting holes at bottom to hold the box against the wall.  I've found that the top of The Dryerbox is held very tight against the wall by the penetrating 4" Snaplock pipe.  The bottom of the Retro-Fit box is best secured to the bottom plate.
• For cutting the Snaplock pipe, these two ideas may work:
  • Use a reciprocating saw with a long fine-toothed metal blade and cut right through the pipe and probably the wall behind it which you can repair easily later
  • Use a Dremel Tool with a cutting disk.  Either cut around the Snaplock pipe exterior or find a way to get inside it and cut from the interior.
• Wearing leather gloves, reach through the top port and attempt to guide and coax the Snaplock pipe through the port opening.  Using small putty knives and crimping the pipe in several places may assist with getting it to penetrate the port. 
• Cut the Snaplock pipe about 1 3/4" from the top edge of the drywall cut.  That will provide sufficient penetrating length to attach the flex hose to later and not be too long where it causes installation headaches when tucking it up.