Just a quickie:
We had planned on taking down the plaster on the west wall, firring it, then spraying it with foam. We figured that we'd need the extra inch of elbow room.
Well, we got to thinking and looking. Two dangerous things, I suppose, but I noticed that in some places the plaster is quite thin. In fact, much of it is LESS than 1". So, how much space are we really going to save? Maybe 5/8"-3/4" on average.
I also noted that we've widened the stair cases anyway by tearing out the bead board and putting in a knee wall. Additionally, we also just REALLY widened the stairs up to the attic as well. When we stiffened the stringer on the first floor, too, that widened the elbow room 1.5" too. So, basically, If we put 1" of foam and 1/2" of drywall, we're a wash, with plenty of space to walk up the stairs.
DW is very pleased to not be tearing down plaster again, and pleased that we don't have to find a place to put it and pleased that we don't have to hire anyone to clean it up and move it.