hip roof and ridge vent

I'm interested in standing seam. My hesitation is that two roofers have told me I don't have enough linear footage for a ridge vent. I have a hip roof (57' 4" x 28') with 1300 sq. ft. of attic floor space and 1605 sq. ft. of roof surface. The ridge is 30 '5" long. One roofer said my pitch was 4:12 and another said 5:12. I have a whole house fan and need 4.3 sq. ft. of outtake venting. Is there any way I can do a standing seam roof with a ridge vent and have enough outtake venting? Is there a special kind of ridge vent to buy or an alteration I would need to make to the ridge? What about aluminum ridge vent on a galvanized roof? Would three turbines be a bad idea? I was told not to go with those for standing seam. Thanks.

You an add more roof venting if you are concerned about the exhaust side of the equation. I would definitely air seal and insulate the attic floor to limit the amount of moisture that goes into the attic in the winter month as that is the time of year that it is problematic.