Vocal/Amp Soundproof Booth Materials

So, I'm ready to build a soundproof (relative) vocal/amp booth. I've found a terrific document - I think - that provides data from laboratory testing by the Institute for Research in Construction at the National Research Council of Canada.   Honestly, I'm not entirely sure how credible this data is for home studio sound applications.  Seems great to me, though. 
 
http://www.nrc-cnrc.gc.ca/eng/ibp/irc.html - document is IR818. 
 
Page after page covers various wall designs and their corresponding transmission loss levels.  This document is geared around building construction, and thus building materials and designs.  My question is about these materials. 
 
For instance, page 75 of this document provides TL data for a wall built with vinyl siding over rigid fiber glass, and then a layer of OSB attached to studs for the exterior layer - cavity filled with insulation - and then the interior layer with resilient channel and two pieces of drywall.  According to the data, this should provide for about 75dB transmission loss at around 1kHZ. 
 
Obviously they are using wall designs you'd expect for a home or building - so walls with drywall on both sides, for instance, are not tested.  So, of those exterior materials, are they really ideal?  Does drywall provide for a better TL than rigid fiber glass sheets?  Should I use OSB in any of these layers?  Or layer it exactly as it says? 
 
Also, is a 75 TL rating very good?  I read that every 6dB drop is half as loud to the ear.  My inexperience with quantifying loudness in dB's leads me to believe that 75 is pretty good.  I need to be able to scream at 2 AM with the family sound asleep upstairs.   
 
 
 
 
 
 

A decent page showing visuals on construction and audio clips to demonstrate the success of such constructions.

http://www.auralexuniversity.com/NeighborsWMA.html

If all you're trying to do is have a vocal booth that allows you to scream in the middle of the night, I think you'll do alright.

And though the site is put together by Auralex, you can still lean alot and cabbage together your own way of doing it.  You might find lots of good info here.

http://www.acoustics101.com/

always remember, it's MASS that stops low frequency.

not insulation.

after that, rock wool is the lightweight choice for dealing with the later freqs.

Everything you need to know is at johnlsayers.com.
Here is a link to his vocal booth design.
Study John's site, download his recording manual, build a room in room with inside/out walls; its all on his site.
Good Luck!