What is the best way to choose mid and high attenuation?

[carbondated]

Hi! I purchased a very nice set of custom speakers that consist of a pair of Altec 414 woofers, an Altec 806 driving a horn, and a JBL 2405 speaker on top. All very well, except that the mid and tweeter crossover sections have attenuators to set the gain!

This should be a good thing, but it feeds the same neurosis that tone controls bring out in me, and I find myself constantly leaping up to change the levels. My friend who built the setup told me to 'trust me ears', which I do -- but they tell me something different every time.

So the question is: Is there a 'correct' setting for the knobs that I can identify by measurement so that I can lock in the ideal attenuation levels for each mid horn and tweeter that is ideal for the speaker and the room and not have to think about them?