Since the first theatre burned in 1820, it would seem that these drawings were made from memory sometime after the old theatre burned. Thus their reliability, especially in details such as the precise arrangement of stairways, comes into question. This would certainly explain the numerous inconsistencies associated with the stairs.
Moreover, neither plan is measured. Indeed, neither is drawn with a straight-edge. Both are free-hand sketches on scraps of paper.
The basic plan of attack in attempting to determine how these sketches relate to the Nisbet/Darley plan and elevation was to develop the location of windows, doors and floors in the computer model using Nisbet/Darley, then attempt to fit stairways sketched by Henry Warren into this framework. Making use of the computer, we followed through on the arrangements suggested by the drawings, over-drawings and erasures on Warren's sketches in an attempt to create a stair-well in which stairways went both to the pit and to the painting room from the level of the stage.
Only the arrangement presented here satisfies these requirements.