Honestly the Har-Bal limiter isn't that great.
Also, matching loudness to some other arbitrary track only based on the arbitrary gain, and trying to have the limiter keep up... is NOT a good practice. Much of perceptive loudness does not come from limiting OR average levels to an extent. For instance the average person can't tell how loud something was that happened more than 7 seconds ago. But there is definitely lots of perception of loudness from the spectral balance, related to the equal loudness curves, and you can use that to your advantage by understanding how that works, and making artificially loud curves. The triple-threat of that is the playback doesn't have to be as loud for the same perception of loudness sensation, and louder-sounding curves also limit more easily if you're careful with your low-end.
The other option, which I use in tandem with the above "by eye/ear" method... is proper metering. I don't know if you've ever used a Dorrough meter, but if you standardize the kind of EQ curve you want to get out of a recording, you can compare the loudness of tracks fairly accurately with one of those.
http://www.dorrough.com/
I don't use Dorrough, but I coded a meter for myself with "dorrough-esc" properties (actually, it's pretty much exactly the same thing
) and it's a very nice thing to have up.
I also use a method of controlling the gain into my final limiter/clipper (which is not public yet, but when it becomes public it's going to make serious waves in the mastering world, i know it) which allows me to always get a near perfect signal level. It's similar to the lower bar on the Dorrough, but with smoother dynamics. I just mastered a 4-track EP last night, and after running ReplayGain on the mp3 encoding of it, from softest to loudest it was 98.4db to 98.7db.
So good metering, combined with consistent spectral balance, goes the mile when it comes to overall consistency of volume. And don't try to arbitrarily match loudness to some other project unless it doesn't at all stress whatever particular limiter you are using to do it. Otherwise you're just ruining the master, imho.