The short question (will accept this as my main answer): What are the
standard depths (from floor - I want something that can be easily
stepped up on by any able-bodied person) and dimensions (the few
largest would suit me - w x h) of the wooden rostrums used in the
theatre, as stages or platforms. By standard, I mean that these must
be available for rent or purchase, worldwide (or local to me - I am in
South Africa, and will be renting from both Cape Town and
Johannesburg)?  You do not have to find me a rental place, I just want
to be sure that when I find the right one, they will have what I am
looking for.

The longer question ($5 tip for this one): I'm working on an
installation that is meant to be a total of 4m x 4m. Inside of this
walled-off space, I can only use a maximum of 4 standard sized
rostrums (which I will rent from a theatre company in South Africa),
to try and cover as much ground as I can.  There will be one entrance,
1m wide (in the bottom-right corner of a floor plan), which must have
a rostrum lined up within a footstep from said entrance (let's say
.25m, unless you have a better suggestion).  The whole thing must be
the same distance from the two walls on the entrance corner (said
footstep).  The rostrum floor space does not have to be square, and I
am willing to lose space on the walls furthest from the entrance, as
well as the bottom-left corner, if need be. Once the first rostrum is
set at the entrance, the others can be spaced from it as you see fit,
but again, no more than a footstep apart where we are not losing floor
space.  Using the biggest, always available standard provided above,
how do I maximize my space? Reminder: I can only use 4 rostrums.