I bought some Owens Corning 703. Now what?

+++ re acousticfields yourube videos. 

I've only been learning this stuff from the videos and from reading, so grain of salt.. 

It's easy(ier) to affect high frequencies than problematic bass, so I would start with the bass traps and getting that under control. By the time you're done with that, you may need less of the high frequency absorbption. If done the other way around, you may do too much of the high frequency absorbption.  That is just my guess. 

The reason for mounting the panels with a space behind them is to make them more efficient. This was mostly for the big bass traps, corner bass traps, that were made for maximum effectiveness because we can never really get enough efficiency at the very low bass notes. You may not even absirb enough with just the 703's. So the diy'er would make a 24 inch wide triangular trap from floor to ceiling and it would be a good idea to have a 1 inch gap to the wall to add even more to its efficiency rating. So it became the norm when giving advise. But if you don't have the ceiling height and you may not even need that particular frequency to be affected, then you may only need the 2 inch or even a 1 inch panel. That's why you are measuring.

Best of luck

Well, Foley says the corners aren't necessarily the spots to be in. He's done thousands of rooms and his data does not support that. He's mentioned it numerous times in his videos. Of course everyone can have their own opinion. 

I suggest watching a few of his videos. He does focus mostly on bass frequencies imo. Maybe because they're the hardest to fix.