What is an "attic air-vent"? Why would the eave and ridge vents not be enough? Did anyone calculate what is needed? Pulling in additional outside summer air could cause moisture problems which is what attic venting is supposed to prevent. If the attic gets too hot you need more insulation rather than more ventilation. Where you live becomes very important in this design effort.

Why would the rafter collar ties need to be 10 ft long? Be sure the installer knows what they are for. Unless the rafters are undersized or sagging the collar ties only need to be immediately under the ridge board and 2x4's would be fine. Of course the longer, lower ties can't do any harm unless they restrict headroom. The rafters should already be tied together through the attic floor and the collar ties only prevent the rafters from separating in a hurricane (as if that would be a concern when the roof would probably already be airborne).

mightyanvil...when the previous roofer put on the new roof he put the ridge vents on but did not cut the ends therefore they are useless plus they are undersized. I have no vents along the top of my 2 cathedral ceilings. I have no rafter collar ties and they need to be 10 ft. long because my attic is huge. The rafters are undersized with 2x4's and should be 2x10's. My home insurance adjuster along with a structural engineer decided what was needed as the moisture problem is very bad & created mold and after this past winter the ice damns caused alot of damage to my recreation room. The bathroom vents along with the whole house fan was just blowing into the attic and having no where to escape. An attic air vent is a dehumidifier/humidifier with a temp control on it to automatically go on/off when needed. This unit was decided once again because of the size of the attic.

in case i am not reading that wrong, you do not use ridge vents AND a powered attic vent. use one or the other.

other than that i don't see anything wrong with the quote.