There IS one additional thing to mention, and that is that the VU meters have their decibel values 'offset' by 12 dB (notice that 0 dB on the VU/Left side is equal to -12 dB on the Peak side) by default in Reason. This doesn't affect the meters in any way, it's just changing the decibel scale.
To get the decibel scale to match the Peak scale, set 'VU Offset" to 0 dB (in the Rack, Hardware Interface, Big Meter section). Otherwise, just remember that for the individual track meters (which use VU), the 0 dB point is -12 dB offset from where it 'really' is (unless you've reset it).
Also, peak levels are more important when trying to avoid clipping during mixing, so focus more on the peak level than the VU level. :-)
Giles Reaves, aka 'selig'
Audio Illusionist, Musical Technologist
Selig Audio, LLC