I use Wavelab 6 and get excellent results. I am not well versed nor do I use the Steinberg plugs for mastering, instead I use the UAD2 mastering suite - Prec EQ, Multiband, Limiter and Maximizer.
My mixes all have a about 3 to 3.5 db of headroom so that I can, if needed, push the volume to 0 db without clipping. The limiter will prevent that once it is set it up. My settings are not for max volume, but they do push the volume high enough to get what I consider a nice volume that competes with commercial material but does not go for killer volume.
The limter input is 4.2 db, the output is -.42db. This is just below 0 db and thus not squashing the track at all. Depending upon the source input level, reduction is always under 1 db. The release time is very fast at .11ms. I could squash any track and really saturate the output by increasing the input gain to 9 or 10 db and I would start to get that “pumping sound.” But I tend to go for a more natural sound. So far so good.
The mastering chain is: EQ, multiband, maximizer and the limiter.