Updating shape dimensions with excel values

[Solvax]

Visio is completely new to me. So I have a few questions to start with.
Let's start with what I am trying to accomplish.

I want to draw a building outline (outer walls) in Visio.
The sizes of these outlines should be based on cell values in excel.

These are the questions I have:
- Is there a way to connect the excel sheet data to the visio shape without having to import the data manually every time? What is your opinion about an ODBC connection?
- What is the best way to draw the building taking into account that the individual lines should resize ? All separate lines (wall shapes)?
- How do I link a specific cell value to a shape dimension in Visio?

Thank you for your kind help!