Is the C++ Builder RAD environment like Delphi's? The Delphi object inspector for forms exposes AutoScroll, AutoSize, and Scaled properties. Also, the inspector exposes Anchor properties for controls. They work great.
When designing GUIs it is often helpful to consider a mouse selection "circle of confusion"... the area around the control which represents the mouse cursor placement error of the typical user... and size/space controls accordingly.
Also, my own method of design is to assume that the user interacts with my software via a touch screen (no one actually does, yet). This causes me to scale and place controls according to "fingertip" width.
But how to estimate fingertip widths on a display whose physical dimensions you can't know in advance?
Most people run their displays at or near their native resolutions, so one can make some approximate DPI assumptions based on calls to GetDeviceCaps. For instance, the native resolution of a 17" display is typically 1024x768... few users run at 640x480 on 17" displays. So if the vertical dimension is, say, 768, and you design for a 15"-19" display at that resolution (and always assume large display fonts and slightly oversized fingertips), your design won't be off by much in most circumstances.
Or skip all of this and use a third party scaler. There are several VCL versions.
My 2 cents.