Re: wrinkles: I prewash and then fold over to dry in my garage so the fabric only has the fold. I do prespray with Best Press, or starch, before ironing and cutting. I like the way the fabric handles - less stretch or distortion - better this way.
I agree with Jan in Va an ironing surface with less padding is better for quqilting.
Re: quilt sizes: For me it varies. For example I live in Arizona so I don't use lots of blankets or a duvet and thus my quilt spread doesn't need to be as large as what I make for my grown kids. They live in upper WI and use mucj more blankets or duvet type things on their beds, so they need more top and drop space.
I only use the drops on the sides and bottom of the bed. If I want to have the pillows covered I either use a pillow drape or make pillow covers. It all depends on what the recipient wants.