You may want to play around with the Normalizing function Opt|Preferences|Arrange. This will boost the Midi tracks volumes.

On the RealTracks, I use around 8 different styles that I have assigned RealTracks to. Rather than play with the volumes within each song, I do a global adjustment for the RealTrack volume within the style editor. Than way, each song I use that style for needs no adjustment using the volume spinners. For example, I use the Acoustic Jazz Bass and found that adjustments from 0 to -5 were required depending on which RT I use (65, 85, 110, 140). Each one was different.

FYI, most of my customized styles that use RealTracks needed volume adjustments. I also found that some RealDrums (Ex: Rhumba) also needed global adjustment.

It takes some time but much easier than playing around with each song.

Rachael