For this exercise you will need a flat cap, set-square, chair and tape-measure.
It's best done with a friend, bearing in mind they may no longer be a friend afterward.
Set the chair against a wall and ~ here's the easy part ~ sit on it. Raise the set square to above head height so as to rest gently on the cap.
Using what's set to be the next hatha yoga move, mark a line on the wall with a pencil level with the base of the set-square.
This, you can tell people at parties, is your height whilst sitting down.
For me that's 52 inches, which at the scale we've chosen to use is around a 44" mark.
It means we can just ~ using artistic licence ~ use one metre uprights that are readily available (in Europe at least) at reduced cost, though we'll rummage in the workshop for the options here.
Don't forget that the tube-connectors add two inches to the height of the 'phone-box' so that we'd be talking nearer the 42" measure.
And frankly nobody would notice the difference on the day.
