I'm designing a house and considering Integraspec.  From a purely design perspective it looks like the perfect exterior wall lengths of 4' 1", 8' 1", 12' 1", 16' 1" etc. for 6" blocks and  for 8" blocks the perfect sizes would be  and 4' 5", 8' 5", 12' 5", 16' 5" etc.  This would use only full panels.  Of course this isn't practical.  Assuming it is possible to design around specific lengths, should I try to stay on even 0.5", 1", 2" or does it even matter that much?

My current thought is that I'll use 8" for the basement primarily due to the backfill height.  For the first floor and garage I'll switch to 6".  I'm thinking it will have a concrete first floor supported by someone's steel trusses.  The transition to 6" will happen once the floor is poured. 

Integraspec's engineering guide goes only to 16' 6" lintels.  I was hoping for a 18' garage door.  I presume an engineer can specify the steel for this.  Does anyone know if it is possible to go that wide for a lintel on a 6" block?  I'll probably have 2' for the header height, but the design isn't done to that level yet.  Of course I don't have the actual roof load to even know if I fit in their table. 

Does anyone know a good engineer that could specify for this build in central Indiana?

Thanks,

Bruce