I went with a 4 leaf assembly
You can't be serious?! A 4 leaf system is terrible!
Pandamonk is dead on as far as 4 leaves are concerned. Hindsight is 20/20 but the info has been here for at least 6 years that I know of. However, he might be wrong because of this:
and put 2 layers of drywall on the outside of the studs.
If you mean you built a DOUBLE wall, with ONE leaf of 2 layers of drywall on the outside face of each wall, then you do NOT have four leaves, you only have two..which is good. However, if you mean you drywalled BOTH faces of each of the double wall frames...then indeed you have a 4 leaf system..not good.
It never ceases to amaze me how many people come here AFTER they build iso assemblies that DON'T do what they thought they would do.
Although, you may have flanking paths that could undermine the BEST Transmission Loss you could build in a wall. Like a coupled floor, common ducts, common exterior walls etc. All must work together or you have the dreaded weak link syndrome...which if this is any indication...
I made a "tunnel" for them in the wall outta just scrap 2 x 4s but I'm sure that needs to be sealed off somehow....
then doing this may be a waste of mass, time and money...
I'm gonna hang two doors with about 15" between them. Each door is about 150 lbs no kidding.
...especially if you just built a 4 leaf wall system to put them in...ie..why put in a double door system with a possible TL rating of 52 if your wall system is a weak link with a TL rating of 43 or your window sytem TL only reaches 39?(hypothetical TL ratings)
Please don't think I'm trying to rain on your parade here though. It sounds as though you've thought this through and may have succeeded. The proof is when you TEST your TL.....ie....at what frequency/SPL will your ISO break down? In other words, what frequency will "cut through like a hot knife through butter?" That is the question.