wall construction and insulation

Insulation question. I've read several posts concerning wallboard/sheetrock but few on the actual type of insulation used. I've heard that using regular household insulation works well, but which R type. I will be putting up side by side 2"x4"x8' walls with a 2" air space between them, then single layer (at this time) of sheetrock. In my area we have typical Lowe's/Home Depot R-13 3.5"x15", faced R-19 3.5"x15", faced R-19 6.25"x15.25" unfaced I've read about 20% compression, but what do you use to compress with a 2" airspace. If 6.25" is used, their will be no air gap. Wall construction question. When building these two wall side by side with air gap, should I still stagger the stud placement so they don't line up with each other? Or is it better to make two identical walls? Thanks for all the help! You guys are great!

For interior walls, you do NOT want faced insulation - yes, standard fiberglass insulation works nearly as well inside a wall as the more expensive, higher density types - arguably, 2.5 PCF SAFB types are optimum for music but it's reportedly less than maybe 2 dB difference at any frequency. I'd need to see your exact intended wall construction to answer about proper thicknesses, etc... Steve

This is a new wall between two existing rooms (replacing an 11' wide x 8' tall according door) The new wall will be two side by side standard 2x4 stud wall, 16" between studs with 1 layer of 5/8" sheetrock on each room side (like that in previous pix). 5/8" sheetrock 2x4 stud wall with insulation 2" air gap 2x4 stud wall with insulation 5/8" sheetrock

If I can't get unfaced, can the facing be ripped off?