XCPUScalar Settings on x50v...over/underclocking

i recently got totally fed up with pockethackmaster, in that i think it is hard to use and not very useful. i gave up and tried
XCPUScalar 2.85, and i really like it with the x50v. it is pretty simple to use, but i have one main question about using the application dependant speed settings.

to save battery power, what is the best strategy u guys use?
on the advanced tab, is it generally best to run apps that use less than 30% on the slowest settings, like 208MHz?
and the apps that run more CPU (>50%), then run more like 524 and 624? i was not sure about this, and wanted to know the proper way to use this.

just to let u guys know, for me, using betaplayer and mp3 listening is good with 208MHz...they usually run about 50%, and 208 works great.