Opening size for Fantastic Fan?

[OCD]

I will soon be putting the roof spars in place for my tear drop, what is the inside measurement needed for a Fantastic Fan to fit comfortably. I haven't ordered mine yet and so would like to have the hole ready to drop it in when it arrives. Also, where it the best place for a Canadian to order one (ie: within Canada or from the US that uses USPS)

Thank you in advance

[LDK]

I believe a 14 1/4" square opening will take care of it. Other opinions may vary alittle.

[aggie79]

I left a 14-1/2" square opening. You probably don't want to go less than 14-1/4" as Larry said or more than 14-1/2".