You are better off using an Isolated Transformer for this scenario.
The Auto Transformer derived from Buck/Boost arrangements are better suited for "Non-Critical Loads", like small Motors, Resistance Heating elements, etc.
A "Buck / Boost" Auto Transformer has poor regulation (+/- 20% at best), with an unstable output Voltage.
For a Project like you have described - driving large numbers of Computers at 240V, using an Isolated Transformer of either Single Phase or 3 Phase would be the better choice.
If Single Phase, go with a 480VAC Primary, to 120/240VAC Secondary.
Ground the Secondary's "Center Tap", but do not use it as an active Circuit Conductor (AKA "Neutral"). Just bond the Grounding Electrode System (GES) to the Center Tap, along with Equipment Grounding Conductors (EGC).
Bring an EGC to the first Panelboard, and use only 2 Pole devices.
If 3 Phase, go with a 480VAC Delta Primary to 240VAC Delta Secondary. "Corner Ground" the Secondary side, or "Center Tap Ground" one winding - but not both!!!
To get really tricked out, use a 480VAC Delta Primary, 240VAC Wye Secondary (Ground the common point), with an "Auxiliary" Delta Secondary for "killing" circulating currents.
Just my 2¢
Scott
