I'm thinking of using 'structural' fiberboard instead of OSB on my cellulose filled double walls with 'thin' brick exterior finish.
Bracerite brand offers 28 perms & r 2 in their 25/32" material which is available in 10" sheets.  I'd use Green Guard 'C2000' or 'Ultrawrap' as the primary air seal/ wrb taped & detailed as the air barrier then Green Guards DC14 rainscreen/drainage plane which is also an r2 insulation.  The DC14 has very low permeability about 1 perm but the drainage would allow the wall to dry while still preventing moisture from the brick being driven inward.  The Ambrico EZ Wall substrate provides additional drainage.  The reason for the fiberboard is the fact that it is much more permeable than OSB, about 28 times as much.  I'm also thinking of using the 1/2" 'Bracerite' on the exterior face of my inner wall to provide an easy inner air seal and a 'service' cavity for wiring and pluming inside the inner air barrier I'd fill the 'service' cavity with UN-faced r 13 to keep my r 40 wall.  The downside of the fiberboard is I must use 16" OC wall framing despite my floor & roof being 24" OC.   With air barriers on both the inner & outer wall, how do I test both?

Edit:
After more reading on the Green Guard site I found that they permit direct attachment of their house wrap to "framing members" without ANY sheathing!  So now I'll substitute a layer of 'Ultra Wrap' for the sheathing (it's 48 to 59 perms, more than the 28 of the sheathing)  on the outer surface of the inner wall.  With a 'burst strength of 145 PSI it's plenty strong to with stand blowing cellulose against it.  This substitution raises my whole wall r by 0.63.  Has anyone defined a 'service cavity' with just house wrap?  If I used 10 foot wide stock on my 9 foot wall & left the remainder at the top it would be easy to staple it to the top of the outer wall for that part of the ceiling air barrier.  Probably best to add a 1x2 on the outside of the top plate for it to wrap over.  Now I need to figure out how to make "ports"  to blow the cellulose through that will seal well.  And answer the question:  How many feet of wall per port?

Edit 2:
As an answer to the how to test both independently, and together question, I propose:  1.  Add what looks like a dryer vent line from the basement to the outdoors  finished & sealed but capped inside (I plan on using vent less clothes dryers) made out of 4" pvc pipe to avoid a terrible thermal bridge.   2.  Add a similar pipe with one end, capped near the capped dryer vent and the other end screened and terminated in the insulation cavity, call this the test vent  3  Test the outer layer alone by removing the cap on the test vent.  4, Test the inner layer alone by coupling the test vent to the dryer vent.  5, Test with both capped for the normal situation of both layers functioning. 
As to the fill ports I'm thinking of adding a 12" tall strip of OSB along the top of the outside of the inner wall, over the housewrap, this would eliminate the furring strip.  Hole saw  blow ports through the house wrap and OSB as required.  After  the blow job  caps, made of OSB, would be screwed in place with a ring of sealant between the cap and house wrap,