Hi,
If you are online only then final drive is not as important as on FM. On FM, it's all about cramming as much of your sound as you can into the modulation limit without going over. The more you push the final drive, the more you will get distortion, albeit not harsh distortion, but also more loudness on FM within the modulation limits.
If you are on the web, then this is not important, yes you need to ensure you do not go above digital maximum but thats all. If you are 1, 3 or 6 dB below maximum, it doesn't matter, the need to be at maximum modulation does not exist.
For web streaming, I would make it sound "nice", yes use processing to keep it sounding even and powerful but you can afford to also have respect for dynamics and can avoid distortion as you are not trying to cram every last bit of loudness out.
Whilst it may seem important to be loud online, it is as daft a concept as the loudness wars on CD, completely unnecessary and making music sound awful.
I'd say your initial setting of -3dB is about right, I certainly wouldn't up it from there in fact I would consider going down until the clipper is not being hit into the red much at all. Your choice of the Plutonium preset is also a very good choice. I tend to leave it set as is but I only adust the speed control, leave it at 50 if you want it to be quite aggressive, for a bit more respect to the dynamics, I back it off, about 20 gives a nice sound.
Yorkie.