Never put one of these in, but it will work best for this job I'm doing, a small bedroon - bath addition. Directions say to keep the esp. between 0 - .36. There is no blower performance charts that come with the unit, so how do I size the duct work? I guess just go in the middle with using .20 as a starting ASP. and see where that takes me? Anybody have eperience with these units?