While the first part may be true, I hope you can see how inflammitory your post is. Many people have played that amp, and therefore we have an idea of how it sounds and how the EQ responds. Yes, use your ears- but it's not wrong to draw on some wisdom and experience of others who've played a particular amp and who knows how it sounds.
Having the OD helps, but for tight low end on a 5150/6505 be sure to tame the lows and resonance and not let yourself turn them too high. Yeah, that cab throbbing sounds awesome- but the lower you go in pitch the more important it becomes to emphasize the mid-range frequencies and roll off the bass. What tuning do you use?
Lowering the gain will also help in a couple areas, like helping tighten the tone and cut noise. With a boost (especially with the volume on it maxed) I would recommend you stay below 4.5-5 on the lead channel, and 6.5-7 on the rhythm channel (w/ crunch and bright engaged). The 5150/6505's have plenty of gain.