Is there a preferred method in setting multiple gains/levels???

Stuff like:

1. Radio's subwoofer, line-out-converter, volume controls

2. Sound processor input/output/levels

3. Amplifiers' gain

Start at the source and move on down the line.

we don't do too much with processors and their indivdiual input/output gains...

but my preferred method of settin an amplifiers gain off a source unit that has a sub out is too crank the sub out on the source and then set the amplifer. that way, when cranked, it's cranked, not clipping.

i imagine one could possibly do the same throwing in the processors gains...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee