Our family's little vacation cottage needs a new roof. I got four
estimates, ranging from $3200 to $10,000 for a 1400 square foot roof.
There are two layers to be stripped off. My questions:

All four roofers offer Certainteed 30 year architectural shingles. There
are two model names, Woodscape and Landmark 30. Does anyone know the
price a contractor would pay for 100 sq ft. of those two shingles? This
would help me to understand what part of these bids might be materials.

One of the roofers offers to use a special "starter course" of
Certainteed shingles. Is this truly useful, or just something to
increase the price?

The house has gable vents and no ridge vent. All four roofers will add a
ridge vent, but one wants to put in soffit venting at the eaves and seal
the gable vents. While I understand the idea behind the soffit venting,
I wonder if it is worth the extra cost.

One roofer proposes 6 nails per shingle vs. 4 nails. We are a mile from
the ocean, and occasionally get a Nor'Easter. However, I doubt that the
current roof had 6 nails and it has lasted well.

It's a lot of questions! I'd be grateful for any insights and info you
might have.

BC