I’m wondering what peoples experiences are with stand alone ERVs and how many are required to service a larger home?

Our current home has the ERV attached to the furnace with separate exhaust fans in the washrooms and laundry as you might expect for a standard home.  However we’re planning a new build that will be very tight  so I’d prefer not to have bathroom exhaust fans that would cause negative pressure in a tight home.  The home is quite large with 3 washrooms upstairs, a powder on the main, as well as a guest room and powder in the basement.  So 4 full washrooms and 2 half in total.  Plus kitchen and laundry.  There are 4 bedrooms upstairs and a guest room in he basement.  About 4100 sqft above grade. 

I see high performance homes online with similar counts that have one stand alone ERV.  But also read that a single ERV doesn’t have enough CFM to support this many rooms so you really require 2 of them.  Which of course is more cost.  I’m wondering what people’s experience is and if there’s a best practice?  We don’t have an unlimited budget so I’m trying to balance performance vs cost.

Thanks!