I had a journeyman HVAC specialist in the house yesterday. He said its "as tight as a drum" leak wise. In his opinion a blower door test isn't needed.
We inspected the existing Honeywell humidifiers. Both are set at 100% humidity and in good order. The house is extremely dry.
You have to remember that the outdoor humidity in Calgary can be as low as 10% when a Chinook is rolling through. These are extreme conditions.
We reviewed my plan to install AA600s for base duty and AA800s for the extreme conditions and he agreed it was a good way to handle the situation.
He calculated the minimum necessary ventilation rate for the house and came up with 280 CFM. Thus he agrees with my desire to install 2 150 CFM HRVs.